Dermatopathology: The Basics

Dermatopathology: The Basics

Dermatopathology: The Basics

Bruce R. Smoller, MD Chair of Pathology Professor of Pathology and Dermatology University of Arkansas for Medical Sciences Little Rock, Arkansas, USA and

Kim M. Hiatt, MD Director of Dermatopathology Associate Professor of Pathology and Dermatology University of Arkansas for Medical Sciences Little Rock, Arkansas, USA

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Bruce R. Smoller University of Arkansas for Medical Sciences Little Rock, Arkansas, USA [email protected]

Kim M. Hiatt University of Arkansas for Medical Sciences Little Rock, Arkansas, USA [email protected]

ISBN 978-1-4419-0023-4 e-ISBN 978-1-4419-0024-1 DOI 10.1007/978-1-4419-0024-1 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2009920686 c Springer Science+Business Media, LLC 2009  All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with re-spect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Preface

In this volume, the authors hope to share their passion for the teaching of dermatopathology with a wide range of students. The idea for the project was initiated by a group of dermatology residents trained during the past 20 years. As part of a dermatopathology curriculum within the Dermatology and Pathology departments, Drs. Smoller and Hiatt have developed a series of didactic lectures covering much of the field. Annually, the residents ask for “hard copies” of the lecture notes and use these to create binders to be used for studying. At their constant urging, we decided to share these lectures in the form of a series of monographs—the first volume of which is presented here. It is not our hope to cover every subtlety in the diagnosis and pathogenesis for every dermatologic diagnosis, but rather to present a framework upon which to base the classification and diagnoses. Within each chapter, a series of related diseases are presented, outlining the major clinical and histologic features and, when appropriate, addressing ancillary techniques. For each entity discussed, we have attempted to provide photographic images to demonstrate the features outlined. Certainly, the goal of this set of volumes is not to supplant, but rather to supplement standard comprehensive textbooks of dermatopathology, by providing a simple infrastructure that will facilitate the learning of myriad facts about each of the entities covered. Along the same lines, there is no attempt to address every dermatologic condition, but rather to concentrate our efforts upon the most common and characteristic entities within each category of disease. It is our sincere hope that v

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Preface

students of dermatopathology will find the classification scheme and the bulleted outlines describing the essential diagnostic features helpful in the mastering of this complex subject.

Acknowledgements

As is always the case with a work of this magnitude, the authors would like to acknowledge the people who have helped to make this work possible. Thus, we would like to thank the members of our wonderful dermatopathology laboratory whose work is depicted in the vast majority of the photomicrographs, including Vicky Givens, Kim Hall, Lori Talley, and R. Peyton Maddox. Dr. Smoller would like to again acknowledge the undying support of his wife, Laura, who continues to be his inspiration and source of energy for these types of endeavors, and his two sons, Jason and Gabriel, for their patience. Dr. Hiatt would like to thank her wonderful husband, Jim, for understanding her ambition to pursue the joys of dermatopathology, including the undertaking of these volumes. She also wants to thank her wonderful children—Stephanie, Nicholas, Kaitlyn and Natalie—for putting so much joy in every day. Finally, she wishes to thank her mentor, colleague, and friend, Bruce Smoller, for all he has done to make this possible.

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Contents

1

Normal Cutaneous Histology . . . . . . . . . . . . . . . . . . . . . Basic Skin Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Epidermis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Keratinocytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Melanocytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Langerhans Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Merkel Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Epidermal Appendages . . . . . . . . . . . . . . . . . . . . . . . . . . Basement Membrane Zone . . . . . . . . . . . . . . . . . . . . . . . . . Basal Keratinocyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lamina Lucida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lamina Densa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sub lamina Densa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dermis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vasculature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Subcutaneous Fat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Skin of “Special Sites” . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 1 1 1 5 6 8 8 17 18 18 19 19 19 20 24 26 29 30

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How to Maximize Information from a Skin Biopsy . . Presumed Neoplastic Processes . . . . . . . . . . . . . . . . . . . . . What is the Differential Diagnosis? . . . . . . . . . . . . . . . . Are the Margins Important? . . . . . . . . . . . . . . . . . . . . . . Melanocytic Neoplasms . . . . . . . . . . . . . . . . . . . . . . . . . Keratinocytic Neoplasms . . . . . . . . . . . . . . . . . . . . . . . .

37 38 38 39 40 41 ix

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Adnexal Neoplasms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dermal Neoplasms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hematopoietic Neoplasms . . . . . . . . . . . . . . . . . . . . . . . Inflammatory Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . Blistering Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “Dermatitis” and “Rash” . . . . . . . . . . . . . . . . . . . . . . . . . Infectious diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Connective Tissue Diseases . . . . . . . . . . . . . . . . . . . . . . Direct Immunofluorescence . . . . . . . . . . . . . . . . . . . . . . Vasculitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Panniculitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alopecia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . Presumed Connective Tissue Nevus, Anetoderma, Epidermal Nevus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rules of Thumb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43 46 49 50 50 52 53 56 57 57 58 59 60 60 61

Special Stains in Dermatopathology . . . . . . . . . . . . . . . Histochemical Stains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Commonly Used Special Stains . . . . . . . . . . . . . . . . . . . . . Periodic Acid-Schiff (PAS) . . . . . . . . . . . . . . . . . . . . . . . . PAS Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alcian Blue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alcian Blue/Colloidal Iron Uses . . . . . . . . . . . . . . . . . . . . Elastic von Gieson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Von Gieson Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brown and Brenn Stain . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acid Fast Stain (AFB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fite Stain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Giemsa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Giemsa Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Warthin-Starry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Masson’s Trichrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Congo Red . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fontana Stain for Melanin . . . . . . . . . . . . . . . . . . . . . . . . . Chloroacetate Esterase . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

63 63 63 64 64 64 65 65 65 66 67 67 67 67 68 69 70 71 71 72

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5

Immunopathology in Diagnostic Dermatopathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tool Box: Antibody Panel . . . . . . . . . . . . . . . . . . . . . . . . . What Is a Tool Box? . . . . . . . . . . . . . . . . . . . . . . . . . . . . Epithelial Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesenchymal Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neuroectodermal Markers . . . . . . . . . . . . . . . . . . . . . . . . . Hematopoietic Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . Requirements for Interpretation . . . . . . . . . . . . . . . . . . . . . Pitfalls in Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . Strategy for Immunopathology . . . . . . . . . . . . . . . . . . . . . Immunopathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Differential Diagnosis of Normal Skin . . . . . . . . . . . . . . Tinea Versicolor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ichthyoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ichthyosis (X-Linked) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ichthyosis (Lamellar) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythrasma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ichthyosis Vulgaris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pemphigus Foliaceus/Erythematosus . . . . . . . . . . . . . . . . Vitiligo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Caf´e-Au-Lait Macule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nevus Depigmentosus (Nevus Achromicus) . . . . . . . . . . Connective Tissue Nevus . . . . . . . . . . . . . . . . . . . . . . . . . . Cutis Laxa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Morphea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anetoderma (Macular Atrophy, Focal Dermal Elastolysis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wrinkling due to Mid-dermal Elastolysis . . . . . . . . . . . . . Dermal Deposition Disorders . . . . . . . . . . . . . . . . . . . . . . . Amyloidosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Localized Cutaneous Amyloidosis . . . . . . . . . . . . . . . . . . Pretibial Myxedema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sclerodema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scleromyxedema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nephrogenic Systemic Fibrosis . . . . . . . . . . . . . . . . . . . . .

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75 75 75 75 78 79 81 84 85 86 87 88 93 94 96 96 97 98 100 101 102 104 105 106 108 110 113 114 114 115 115 117 119 121 122

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Conditions with Minimal Inflammation . . . . . . . . . . . . . . Small Plaque (Guttate) Parapsoriasis (Digitate Dermatosis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Urticaria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Urticaria Pigmentosa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

124 124 126 126

Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Chapter 1

Normal Cutaneous Histology

Basic Skin Anatomy • Epidermis – varies in thickness with site, but ranges from < 0.1 mm on the eyelids to about 1 mm on acral sites • Dermis – varies in thickness with site, but ranges from 1 mm on the face to 4 mm (approximately) on the back • Subcutaneous fat – varies extensively in thickness (up to multiple cm)

Epidermis Keratinocytes • Epidermis with stratified layers – – – –

Stratum corneum Stratum granulosum Stratum spinosum Stratum basalis

B.R. Smoller, K.M. Hiatt, Dermatopathology: The Basics, DOI 10.1007/978-1-4419-0024-1 1,  C Springer Science+Business Media, LLC 2009

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1 Normal Cutaneous Histology

Fig. 1.1 Overview of the epidermis demonstrating normal keratinocyte maturation (×200)

Stratum Corneum • Normal pattern – basket-weave orthokeratosis – Caused by increased lipid concentration in keratinocyte cytoplasm (Odland bodies) – Basket-weave pattern is not seen on frozen section • Nuclei are normally extruded before keratinocytes reach the stratum corneum – Retained in conditions of dysmaturation and hyperproliferation (valuable clue to diagnoses)

Epidermis

Fig. 1.2 (×400)

3

The stratum corneum demonstrates basket-weave orthokeratosis

Stratum Granulosum • Keratohyaline granules characterize this layer • Profilaggrin involved in appropriate clumping of keratin in preparation for transformation to stratum corneum – Histidine-rich granules – Defect in profilaggrin seen in ichthyosis vulgaris (no granular layer present) • Involucrin and keratolinin also appear as substrate for transglutaminase in cross linking of cellular envelope at this level

Stratum Spinosum • Zone of maturation • Takes basal cell 14 days to reach the stratum corneum and another 14 to desquamate under normal conditions

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1 Normal Cutaneous Histology

• Nuclear:cytoplasmic ratio becomes progressively smaller in these layers • Keratin production switches from lower molecular weight (cytokeratin 5 and 14) to higher molecular weights (mainly keratins 1 and 10)

Fig. 1.3 The stratum granulosum demonstrates keratinocytes with abundant keratohyaline granules. The spinosum layer keratinocytes have abundant eosinophilic cytoplasm (×400)

Stratum Basalis • Cells at base of rete ridges are stem cells that proliferate most rapidly • Basal cells at tips of dermal papillae proliferate slowly • Basal cells produce lowest molecular weight keratins (of all keratinocytes) – keratins 5 and 14

Epidermis

5

Fig. 1.4 The basal layer demonstrates pigment-laden keratnocytes and vacuolated melanocytes (×600)

Melanocytes • Every tenth cell along basal layer is a melanocyte (on average) – Increased in hyperpigmented and sun-exposed body sites – Decreased on palms and soles • Each melanocyte “serves,” via dendritic processes, 36 keratinocytes with melanin (on average) • Increased numbers of melanocytes with sun exposure • Produce eumelanin (brown and black) and phaeomelanin (red brown – higher in sulfur content) • Transfer melanosomes to lysosomes within keratinocytes via phagocytosis • Individual variation in skin color is a function of relative numbers of stage I–IV melanosomes. In general, all individuals have the same numbers of melanocytes (more stage IV in darker skin, more stage I in lighter skin)

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1 Normal Cutaneous Histology

• Darker races have larger, singly dispersed melanosomes in keratinocytes • Caucasians have melanosome complexes within keratinocytes

Fig. 1.5 Cells with hyperchromatic nuclei and surrounding spaces along the basal layer (arrows) are melanocytes (×600)

Langerhans Cells • • • • • •

Mid-epidermal dendritic cells Constitute 3–4% of all epidermal cells Involved in antigen presentation Bone marrow derived Express HLA-DR, ATPase, S100, CD1a Electron microscope demonstrates Birbeck granules, a pentalaminar structure shaped like a tennis racquet when viewed in full longitudinal section • Increased numbers in conditions with increased antigen presentation (i.e., contact dermatitis) • May coalesce into “microgranulomata” simulating nests of melanocytes

Epidermis

7

Fig. 1.6 Langerhans cells appear as hyperchromatic nuclei with surrounding spaces in the mid-straum spinosum (×600)

Fig. 1.7 CD1a demonstrates the dendritic nature of the intraepidermal Langerhans cells (×600)

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1 Normal Cutaneous Histology

Merkel Cells • • • •

Part of the sensory nervous system Sit on basement membrane Have desmosomal contacts with keratinocytes Haarscheibe – one free nerve ending from dermis touches up to 50 Merkel cells to form this unit • Merkel cells produce keratin (cytokeratin 20) and neurosecretory granules • Not detectable with routinely stained histologic sections

Epidermal Appendages • • • •

Hair follicles Sebaceous glands Eccrine apparatus Apocrine glands

Hair Follicles • Anagen phase – comprises 84% of hairs – Actively growing hairs – Hairs remain in anagen phase for about 3 years • Catagen phase – about 2% of hairs – Resting phase hairs – Hairs remain in catagen phase for about 3 weeks

b

Unimportant percentage for evaluating types of alopecia (can be grouped with “non anagen” for assessment in histologic evaluations of alopecia)

• Telogen phase – 14% of hairs – Involuting hairs – Hairs remain in telogen phase for about three months

Epidermis

9

Hair Follicle Anatomy (Anagen Phase) • Ostium – opens to external surface of skin • Acrotrichium – intra epidermal portion of follicle • Infundibulum – extends from insertion of sebaceous duct to epidermis (granular layer present – contains histidine-rich trichohyaline granules) • Isthmus – extends from insertion of arrector pili muscle to insertion of sebaceous gland (no granular layer present) • Lower portion – dermal hair papilla, matrix, hair (including medulla, cortex and cuticle), inner root sheath, and outer root sheath

Fig. 1.8 Acrotrichium of hair follicle opening onto skin surface (×100)

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1 Normal Cutaneous Histology

Fig. 1.9 Lower portion of anagen phase hair demonstrating outer root sheath, inner root sheath, hair matrix and papillary mesencymal body (×200)

Fig. 1.10 Hair bulb with matrix and papilla (×400)

Epidermis

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• Catagen phase – Mitoses no longer present, bulb shrinks and separates from dermal hair papilla – Lower portion involutes via apoptosis and becomes a thin cord surrounded by wrinkled folds

Fig. 1.11 Catagen phase hair with small bulb located high in dermis and loss of outer root sheath (×100)

• Telogen phase – Thin epithelial cord retracts along with papilla – Lowest portion now at level of arrector pili – Hair surrounded by outer root sheath (inner root sheath disappears)

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1 Normal Cutaneous Histology

Fig. 1.12 Telogen phase hair with deepest portion located at level of arrector pili muscles within the dermis (×200)

Sebaceous Glands • • • •

None on palms and soles Many on face (especially nose) Ectopic glands on mucous membranes are called Fordyce spots Meibomian glands on eyelids and Montgomery tubercles on areolae are sebaceous glands • Glands empty into hair follicle at level of the follicular infundibulum • Large at birth, smaller pre pubertal, then enlarge again during puberty (under hormonal control)

Epidermis

13

Fig. 1.13 Sebaceous glands open into hair follicles at the level of the infundibulum (×100)

Eccrine Glands • Highest density on palms and soles • Absent on lips, nail beds, labia minora, glans penis • Secretory glands – Layer of secretory cells surrounded by myoepithelial cells

b

Two types of cells in secretory layer

– Large, vesicular cells – Small, dark, cuboidal cells

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1 Normal Cutaneous Histology

Fig. 1.14 Eccrine ducts demonstrate small cuboidal epithelium without a surrounding myoepithelial level (×600)

Eccrine Ducts • Acrosyringium is an intra-epidermal portion of duct, the portion of the duct within the reticular dermis is simply referred to as the dermal duct • Eccrine apparatus empties directly into epidermis and not into hair follicles (unlike apocrine and sebaceous glands) • No myoepithelial layer in eccrine ducts

Epidermis

15

Fig. 1.15 Eccrine glands have larger cells with more eosinophilic cytoplasm and surrounding myoepithelial cells (×400)

Fig. 1.16 The acrosyringium is the intraepidermal portion of the eccrine duct that empties directly onto the skin surface (×100)

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1 Normal Cutaneous Histology

Fig. 1.17 Eccrine glands are more eosinophilic and are surrounded by cells with more cytoplasm (arrow) than the eccrine ducts (×200)

Apocrine Glands • Highest concentration in axilla, inguinal region, peri anal • Moll’s glands (eyelids) and ceruminous glands (ears) are apocrine glands • Apocrine glands empty into hair follicles at the highest point in infundibulum (right below epidermis) • Only secretory cells in the secretory portion (no myoepithelial cells, unlike in eccrine glands)

Basement Membrane Zone

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Fig. 1.18 Aprocrine glands have abundant eosinophilic cytoplasm with apical hobnailing into the lumin (×200)

Basement Membrane Zone • Ultrastructural terminology – components not apparent with routine histologic sections – – – –

Basal keratinocyte Lamina lucida Lamina densa Sublamina densa

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1 Normal Cutaneous Histology

Fig. 1.19 Electron microscopic demonstration of basal keratinocyte, lamina lucida, lamina densa, and sublamina densa (×30,000)

Basal Keratinocyte • Attaches to underlying zone by hemidesmosomes • Hemidesmosomes are partially formed by a plaque of tonofilaments • Bullous pemphigoid antigen II is actually present within the cytoplasmic hemidesmosomal plaque in the cytoplasm of basal keratinocytes • Site of blister in epidermolysis bullosa simplex (most subtypes) – caused by mutations in keratins 5 and/or 14 within basal keratinocytes

Lamina Lucida • 20–40 nm wide, electron-lucent zone • Anchoring filaments course through the lamina lucida • Bullous pemphigoid antigens II and I are both present within this layer

Dermis

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• Laminin and fibronectin are present in lamina lucida • Site of blister in bullous pemphigoid, junctional type of epidermolysis bullosa

Lamina Densa • Electron-dense zone beneath lamina lucida (30–60 nm) • Anchoring fibrils (which are made up of type VII collagen) are present • Laminin is present • Type IV collagen is present as main constituent of this layer

Sub lamina Densa • Origin of anchoring fibrils (type VII collagen) • Site of blister in bullous lupus erythematosus, dystrophic and acquired epidermolysis bullosa, and dermatitis herpetiformis

Dermis • Vasculature • Connective tissue – Collagen – Elastic tissue • Nerves • Muscle • Inflammatory cells – Dermal dendrocytes – Lymphocytes – Fibroblasts

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1 Normal Cutaneous Histology

Vasculature • Deep vascular – plexus present at junction of reticular dermis and subcutaneous fat – Oriented parallel to the surface of the skin • Feeder vessels – oriented perpendicular to epidermal surface, connect superficial and deep vascular plexuses • Superficial vascular plexus – separates papillary from reticular – dermis parallel to surface of skin • Post capillary venules – extend from superficial vascular plexus into dermal papillae • Recognition of these structures and identification of them is important for: – Assessing Clark’s levels with melanoma – Determining pattern of dermal involvement with inflammatory conditions (superficial vs. superficial and deep perivascular inflammation)

Fig. 1.20 Deep vascular plexus separates the deep reticular dermis from the underlying subcutaneous fat and is oriented parallel with the surface of the skin (×200)

Dermis

21

Fig. 1.21 Feeder vessels course through the dermis perpendicular to the surface of the skin (×100)

Fig. 1.22 The superficial vascular plexus separates the papillary from the reticular dermis and courses parallel to the surface of the skin (×200)

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1 Normal Cutaneous Histology

Collagens • Type I – main constituent of reticular dermis; also present in papillary dermis – Big, thick eosinophilic bundles • Type II – major component of cartilage • Type III – present in large quantities in papillary dermis and in newly formed scar tissue and fetal dermis – Smaller bundles and less eosinophilic than type I collagen • • • •

Type IV – basement membrane collagen Type V – in fetal membranes and vascular tissue Type VI – in neurofibromas Type VII – anchoring fibrils

Fig. 1.23 Large bands of eosinophilic collagen oriented vaguely parallel with the skin surface comprise the reticular dermis (×200)

Dermis

23

Fig. 1.24 Type II collagen comprises cartilage that is found deep to the dermis in biopsies from the nose and the ear (×400)

Elastic Tissue • Oxytalin – thin fibers, perpendicular to DEJ in papillary dermis – Major target in solar elastosis • Elaunin – network of fibers oriented parallel to DEJ in upper reticular dermis, give rise to oxytalin fibers; rich in microfibrils with little elastin • Elastic fibers in deep reticular dermis – much larger, connect to elaunin fibers

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1 Normal Cutaneous Histology

Fig. 1.25 Elastic tissue fibers become more pronounced with prolonged sunexposure (×200)

Nerves • Mucocutaneous end organs – cannot be recognized on routine sections – Present on lips and genital skin • Meissner’s corpuscles – present exclusively on ventral surfaces of hands and feet and are seen in about every fourth dermal papilla – Serve as touch receptors • Pacini-Vater corpuscles – subcutaneous; most common on fingers and toes – Serve as pressure receptors • Autonomic – innervate vessels, smooth muscle, apocrine and eccrine (but not sebaceous) glands – Not visible on routine histologic sections

Dermis

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Fig. 1.26 Meissner’s corpuscles are present within approximately every fourth papillary dermal tip (×400)

Fig. 1.27 Pacinian corpuscles are present in the deeper dermis in acral skin (×100)

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1 Normal Cutaneous Histology

Muscles • Arrector pili – Smooth muscle around vessels and hairs – Pilar type insert at isthmus of hair follicles – Autonomically innervated • Glomus cells – Mainly in nail beds of fingers and toes – Surround arterioles at Suquet-Hoyer canal

Fig. 1.28 Arrector pili muscles (pilar) are located in the mid-reticular dermis and attach to hair follicles (×100)

Dermis

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Fig. 1.29 Glomus cells are prevalent surrounding dermal blood vessels in acral skin (×400)

Dermal Dendrocytes • • • • •

Putatively bone marrow-derived cells Reside in dermis Involved in antigen presentation Spindle-shaped cells resemble fibroblasts on routine sections Express factor XIIIa (transglutaminase from coagulation cascade) – useful for immunohistochemical identification of these cells • Increased in many immune responses • May be cell of origin in dermatofibroma

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1 Normal Cutaneous Histology

Fig. 1.30 Spindle-shaped dermal dendrocytes are present within the papillary and reticular dermis (×600)

Lymphocytes • Normally present in small numbers around vessels of superficial vascular plexus • 80% T cells, 20% B cells, almost no natural killer cells • 3–4× more CD4+ than CD8+ cells

Mast Cells • Normal around vessels in superficial vascular plexus • Can appear spindled and resemble fibroblasts • Up to six can be seen normally around each vessel in inflammatory states

Subcutaneous Fat

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Fibroblasts • Present within dermis • Responsible for producing types I and III collagen normally found in dermis • Not all dermal spindle cells are fibroblasts (mast cells, dermal dendrocytes, pericytes are all present and may appear spindled) • Unclear relationship between fibroblasts, histiocytes, and tumors with “fibrohistiocytic” differentiation

Fig. 1.31 Fibroblasts appear as spindle-shaped cells in the dermis, interspersed between collagen bundles (×600)

Subcutaneous Fat • Lobular aggregations of adipocytes separated by fibrous septa • Adipocytes with eccentric nuclei and single large vacuole in cytoplasm containing fat • Nerves and vessels course through septa at an angle to the surface epithelium, but nearing perpendicular

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1 Normal Cutaneous Histology

• Thickness of pannus related to weight of person, unlike thickness of dermis and epidermis (which have site-specific thicknesses but do not correlate with weight)

Fig. 1.32 The subcutaneous fat is organized into lobules of adipoctes surrounded by fibrous septa (×40)

Skin of “Special Sites” • Acral skin – Stratum corneum much thicker than elsewhere – Presence of stratum lucidum at base of stratum corneum (clear zone separating stratum corneum from stratum granulosum) – Epidermis thicker than on trunk or extremities – Relatively fewer melanocytes in epidermis – Meissner’s corpuscles in papillary dermal tips – Increased dermal collagen with diminished space between bundles – No pilosebaceous units, many eccrine structures

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Fig. 1.33 Marked hyperkeratosis, thick epidermis, and thickened dermal collagen bundles devoid of pilosebaceous units characterize acral skin (×40)

Fig. 1.34 Marked hypergranulosis, compact orthokeratosis, acanthosis, and ectatic blood vessels within the papillary dermal tips are seen within acral sites (×100)

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• Eyelid – Very thin stratum corneum and epidermis – Goblet cells (large clear cells) are scattered throughout the epidermis – Abundant vellus hairs and sebaceous glands – Very thin, wispy collagen – Very thin dermis

Fig. 1.35 Eyelid skin is characterized by scattered goblet cells within the epidermis and thin dermis with wispy collagen bundles and abundant vellus hairs (×100)

• Nails – – – – –

Dense orthokeratotic plate – no basket weave appearance Rete ridge pattern varies from other sites Melanocytes present but less dense than in other body sites Very dense collagen with widely ectatic vessels No cutaneous appendages

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– Histologic patterns vary with site in nail (i.e., proximal nail fold that has a granular layer vs. matrix that does not)

Fig. 1.36 The nail has a micro-anatomy in which regions retain a granular layer (proximal nail fold) and others in which it is absent (nail bed) (×100)

• Nipple – Acanthotic epidermis with overlying orthokeratosis may be slightly papillomatous – Hyperpigmented basal layer with slight increase in melanocytes – Enlarged sebaceous glands – Glandular epithelium may be present in dermis – Abundant smooth muscle bundles in reticular dermis

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1 Normal Cutaneous Histology

Fig. 1.37 Nipple skin demonstrates papillomatosis, acanthosis, prominent sebaceous glands, abundant smooth muscle bundles, and glandular epithelium (×400)

• Mucosa – Mucosa is NOT skin – important to recognize differences:

b b b b b b

Parakeratosis is normal in mucosa, and one does not see “basket-weave” orthokeratosis No granular layer is present (unless traumatized) Keratinocytes have abundant glycogenization (and appear very pale) No pilosebaceous units are present (except with anomalous Fordyce spots) Plasma cells are a normal part of inflammatory infiltrate in submucosa Salivary glands and ducts may be present

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Fig. 1.38 Mucosa lacks a granular layer and cutaneous appendages. Keratinocytes are well-glycogenated (×100)

Chapter 2

How to Maximize Information from a Skin Biopsy

Questions to consider prior to obtaining tissue from the patient: • What information do I want from this biopsy specimen? • What is the best piece of tissue to send to the pathology laboratory? • Are there particular tests needed that would require special fixation techniques in order to answer the question posed? Answers to the above depend on the condition to be biopsied • Presumed neoplasms – – – – –

Melanocytic Keratinocytic Adnexal Dermal Hematopoietic

• Inflammatory conditions – – – – – –

Blistering processes “Dermatitis” or “rash” Infectious diseases Connective tissue diseases Vasculitis Panniculitis

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– Alopecia • Rare entities

Presumed Neoplastic Processes What is the Differential Diagnosis? This is a crucial point prior to doing the biopsy. • If melanoma is in the differential diagnosis: – Complete visualization of the basal layer is crucial – There needs to be enough dermis to evaluate for maturation

Fig. 2.1 Lesions that are clinically worrisome for melanoma need to be biopsied deep enough to allow for measurement of depth. Ideally, there will be normal tissue below the neoplasm

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– If the lesion is melanoma, then a depth measurement is needed, so there must be normal tissue beneath the tumor (Fig. 2.1) – Depth measurements on re-excision specimens are notoriously unreliable – first chance is the best for accurate data – Electrodessication, curettage, and very thin shave biopsies may obscure this information

Are the Margins Important? • Elliptical excisions (oriented) provide the best way to assess margins with routine histopathology – Mohs surgery may provide more complete information, but is not readily available for all cases • Deeper shave biopsies (saucerization) may also permit evaluation of surgical margins in some cases (Fig. 2.2) • Punch biopsies will allow evaluation of margins if large enough to completely excise the lesion in question (Fig. 2.3)

Fig. 2.2 On occasion, a deep shave biopsy may be adequate for evaluating lateral and deep margins

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Fig. 2.3 For small lesions, punch biopsies may allow adequate margin evaluation

Melanocytic Neoplasms • Elliptical excisions are best for determining depth and margins of excision • A shave biopsy may not be deep enough to get beneath the dermal component for accurate assessment of Breslow thickness • A punch biopsy may not allow for evaluation of circumscription as a diagnostic feature

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Keratinocytic Neoplasms • A deep shave or punch biopsy is ideal, as a shave biopsy that is too shallow: – May not permit distinction of squamous cell carcinoma from squamatized basal cell carcinoma – Will not allow for precise subtyping of basal cell carcinoma variant (and likelihood of local recurrence) (Fig. 2.4)

Fig. 2.4 This shave biopsy of a basal cell carcinoma does not provide adequate lesional tissue to confidently diagnose the tumor type

• Pathologists tend to err on the side of malignancy when presented with small samplings of neoplastic processes • Actinic keratoses or irritated seborrheic keratoses could be misdiagnosed as squamous cell carcinoma if incompletely visualized (Fig. 2.5)

Fig. 2.5 The cytologic atypia, large nuclei, and prominent nucleoli (A) in this irritated seborrheic keratosis may be mistaken for malignant atypia of a squamous cell carcinoma without the benefit of the overall morphology (B)

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• A deep shave biopsy or a punch biopsy are the recommended specimens as a specimen that is too shallow can make it very difficult to distinguish – Basal cell carcinoma from trichoepithelioma (Fig. 2.6)

A

B

C Fig. 2.6 This shave biopsy of a syringoma (A) is too shallow to allow for confident distinction from the superficial portion of other basaloid lesions such as basal cell carcinoma (B) and trichoepithelioma (C)

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A

B

C

D

Fig. 2.7 A shallow shave biopsy can make a morpheaform basal cell carcinoma (A), a desmoplastic trichoepithelioma (B), and a syringoma (C) very difficult to distinguish from the aggressive look-alike microcystic adnexal carcinoma (D)

– Microcystic adnexal carcinoma vs. trichoepithelioma vs. syringoma vs. morpheic basal cell carcinoma (Fig. 2.7) – Squamatized basal cell carcinoma vs. squamous cell carcinoma – Precise names of appendage tumors that are primarily dermal-based

Adnexal Neoplasms • For dermal nodules thought to be adnexal in etiology, excisional biopsy allows evaluation of the overall architecture of the lesions as well as tumor edge to assess for invasion (Figs. 2.8–2.10)

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A

B Fig. 2.8 Excisional biopsy is ideal for adequate evaluation of all portions of dermal tumors. The infiltrative border, cytologic atypia, and mitoses (A) of this tricholimmalcarcinoma (B) may not be appreciated in a partial biopsy

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A

B Fig. 2.9 The large pleomorphic nuclei and numerous mitoses (A) indicating malignant transformation in this spiradenocarcinoma (B) may be missed in a partial sample

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Fig. 2.10 Unlike the other examples, without the benefit of the overall architecture, a partial sampling that shows nuclear atypia and mitoses (A) may be mistaken as features of malignancy in this benign proliferating pilar cyst (B)

Dermal Neoplasms • For tumors of mesenchymal etiology, a punch biopsy allows enough lesion to evaluate for tumor type • A deep biopsy to assess the deep margin, in particular the interaction of the tumor with the subcutaneous tissue is important (Fig. 2.11) • Differentiating dermatofibroma, cellular dermatofibroma, and dermatofibrosarcoma protuberans requires an interpretation of how the tumor is interacting with the subcutaneous tissue (Fig. 2.12)

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A

B

Fig. 2.11 A shave biopsy of a dermal tumor often gives adequate histologic information as in this dermatofibroma (A). However, a punch biopsy allows for evaluation of the deep margin of the tumor and enables a more confident diagnosis (B)

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A

B

C

Fig. 2.12 Among other histologic features, the interaction of the deep portion of a dermal infiltrate with the subcutaneous tissue is critical for a definitive diagnosis as shown here by the lack of involvement in a classic dermatofibroma (A), the tracking along the subcutaneous septae of a cellular dermatofibroma (B), and the invasion of the entire subcutaneous lobule by a dermatofibrosarcoma protuberans (C)

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Hematopoietic Neoplasms • A punch biopsy is the ideal specimen (Fig. 2.13) • A shave biopsy is not recommended as it precludes complete analysis of the dermal architecture • Frozen tissue is no longer necessary for a lymphoma/leukemia work-up: – Immunostains used in diagnosis will all recognize formalinfixed, paraffin-embedded tissue – Gene rearrangement studies, such as polymerase chain reaction (PCR), work adequately on fixed tissue specimens with sufficient infiltrate to harvest lesional DNA

A

B

Fig. 2.13 For presumed hematopoietic infiltrates, a punch biopsy allows for the most complete interpretation, as in this example of benign cutaneous lymphoid hyperplasia (A) and cutaneous marginal zone lymphoma (B)

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Inflammatory Processes Blistering Diseases • A punch biopsy from the edge of the blister (newest portion) is the ideal specimen – Least secondary change (i.e., ischemia) is present at the edge of specimen (Fig. 2.14) • Deep shave biopsy, including entire blister, is also useful in some cases • Elliptical excisions are not ordinarily required

Fig. 2.14 A biopsy from a blister should be taken at the edge of the biopsy to include both blistered and intact skin

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• Direct immunofluorescence is helpful in most cases (Fig. 2.15) – Tissue from perilesional skin is ideal – Punch biopsy is probably the best choice biopsy – Tissue from the blister itself is associated with increased levels of false negative results as the associated inflammatory infiltrate is effective in scavaging the immune deposit. – Fresh skin soaked in high salt concentration encourages the epidermis to separate from the dermis along the lamina lucida. A specimen under these conditions can then be

Fig. 2.15 Direct immunofluorescence can be helpful in further elucidating the etiology of a blister, as in this case of dermatitis herpetiformis

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subjected to direct immunofluorescence for more accurate determination of the location of the auto-antibody deposition (Fig. 2.16)

Fig. 2.16 Utilizing the salt split-skin technique is helpful in determining more accurately the location of the immune deposit with respect to the lamina lucida as in this case of epidermolysis bullosa acquisita in which the deposit is along the floor of the blister—i.e., corresponding to the site of collagen VII

• Tissue must be frozen – cannot be exposed to formalin or direct immunofluorescence procedure will not work • To preserve antigenicity, the specimen can be placed on a saline-soaked gauze, not drenched, for a few hours or in Michel’s fixative for up to a week

“Dermatitis” and “Rash” • A punch biopsy is the procedure of choice

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• This allows for adequate interpretation of epidermal changes (spongiotic or interface), as well as the pattern of inflammatory infiltrate (superficial and/or deep, perivascular, periappendageal or diffuse) and characteristic inflammatory cells (lymphocytes, plasma cells, and/or eosinophils) (Fig. 2.17) • Best to biopsy a new lesion • If there are multiple morphologies clinically, several 3 mm punch biopsies depicting each morphology will maximize the chances of making a definitive diagnosis

A

B

Fig. 2.17 For a “dermatitis”, a punch biopsy is the ideal procedure for evaluating both the epidermal changes and the characteristics of the dermal infiltrate, as in this case of dermal hypersensitivity reaction (A) and seborrheic dermatitis (B)

Infectious diseases • For suspected tinea, human papilloma virus, or herpes simplex virus, infections, the epidermis is the most critical site and a shave biopsy is adequate (Fig. 2.18) unless follicular involvement is suspected, in which case a punch biopsy is preferred

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A

B

Fig. 2.18 A shave biopsy is ideal for superficial infections, in particular tinea, herpes simples virus (A), and human papilloma virus (B)

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• For all other infectious etiololgies, dermis is usually the most important site. Accordingly, a punch biopsy provides the ideal specimen type (Fig. 2.19). For deep fungal infections with exuberant pseudoepitheliomatous hyperplasia, a second punch biopsy within the site of the initial biopsy may be necessary to obtain adequate dermis for evaluation • Elliptical excisions are not ordinarily necessary • Tissue should be bisected at the time of biopsy (prior to placing in formalin) with half submitted to appropriate tissue cultures • Tissue culture is more sensitive and specific for infectious etiologies than is morphologic examination • Special stains and PCR techniques will work on formalin-fixed tissues, so no necessary special fixation

Fig. 2.19 A punch biopsy, as is this case of mycobacterium leprosum, provides the ideal diagnostic specimen

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Connective Tissue Diseases • Punch biopsy is the best choice (Fig. 2.20) • Tissue taken must include epidermis, dermis and ideally, a small bit of superficial subcutaneous fat • Shave biopsies will NOT demonstrate the pathologic changes • Lesional skin is best to biopsy for routine histology, as well as for direct immunofluorescence studies – requires freezing or Michel’s fixative

Fig. 2.20 Suspected connective tissue disorders require a punch biopsy to evaluate for deep dermal inflammatory infiltrate

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Direct Immunofluorescence • Lupus band test • Granular deposits of IgG, IgM, C3 and sometimes IgA are deposited along the dermal-epidermal junction and can be detected by direct immunofluorescence (DIF). The ideal site to detect this deposition is: – Lesional skin for discoid lupus, systemic lupus (SLE), and subacute lupus (SCLE) – Nonlesional, sun exposed skin for SLE and some SCLE – Nonlesional, nonsun exposed skin shows deposition only in SLE • SCLE and lupus profundus often have negative lupus band tests • Older lesions are often negative

Vasculitis • Punch biopsy is ideal choice of biopsy (Fig. 2.21) • Pathologic findings are in the dermis • Best to biopsy lesions less than 24 hours old – older lesions have more confounding, secondary changes and fewer transmural neutrophils • Lesional skin is the best to biopsy • DIF is helpful to rule out Henoch-Schonlein purpura, which will show vascular IgA deposits – best results with newest lesions (requires frozen tissue)

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Fig. 2.21 A punch biopsy to assess for vasculitis allows for evaluation of small vessels in the superficial dermis, as in this case of leukocytoclastic vasculitis and larger vessels in the reticular dermis

Panniculitis • A small elliptical incisional biopsy is ideal • A deep punch biopsy, or a punch biopsy within a punch biopsy, is the second choice, but fat often retracts away from dermis during extraction (Fig. 2.22) • Pathology is centered in subcutaneous fat, thus a shave biopsy will not produce interpretable findings • No special fixation techniques are required for the diagnosis of most panniculitides

Inflammatory Processes

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B

Fig. 2.22 To evaluate for deep dermal and subcutaneous processes, it is critical that the biopsy is deep enough to include this tissue, as in this case of erythema nodosum (A) and nephrogenic systemic fibrosis (B)

Alopecia • 4 mm punch biopsy is best choice • Most published quantitative studies are done on 4 mm punch biopsies • Transverse sectioning allows for evaluation of all follicles in one horizontal plane (Fig. 2.23) • The biopsy should be taken from an active, advancing edge of alopecia or the lesion is likely to show no diagnostic features and possibly only end-stage fibrosis • It is important to relate to the pathology lab that this punch biopsy is not a conventional skin punch biopsy. Indicating “alopecia work-up” on the pathology requisition form is recommended • This specimen requires no special fixation, but the transverse sectioning requires a different embedding technique by the laboratory • Two separate punch biopsies may allow for parallel processing (transverse and vertical sectioning) – preferred by some pathologists

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Fig. 2.23 Published studies of alopecia are most often based on transverse sections of 4 mm punch biopies

Miscellaneous Conditions Presumed Connective Tissue Nevus, Anetoderma, Epidermal Nevus • Ideal biopsy is a thin, elliptical incisional biopsy traversing normal skin at one tip and lesional skin at the other • Best to ink one tip so that the pathologists know to orient the ellipse differently from the standard procedure for processing elliptical excisional biopsies • This will allow direct comparison of subtle dermal changes between lesional and peri-lesional skin

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Rules of Thumb • Formulate the reason for the biopsy and know the anatomic location of the presumed pathology within the skin PRIOR to performing the procedure • Contact the pathologist PRIOR to performing the biopsy if there is any uncertainty about the ideal biopsy type or fixation/storage methods required

Chapter 3

Special Stains in Dermatopathology

Histochemical Stains • Used to highlight characteristics of tissue not easily identified with routine hematoxylin and eosin • Much less expensive than immunostaining if both options are available • Readily available in virtually all dermatopathology settings

Commonly Used Special Stains • • • • • • • • • • • •

Periodic acid-Schiff (PAS) with and without diastase Alcian blue/Colloidal iron Elastic von Gieson Brown and Brenn (tissue gram stain) Acid fast stain/fite Giemsa Warthin-Starry Masson’s trichrome Congo red Fontana stain for melanin Chloroacetate esterase Perls

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Periodic Acid-Schiff (PAS) • Used to demonstrate presence of neutral mucopolysaccharides, especially glycogen • Positive stain is red • Oxidation of hydroxy groups in 1,2 glycols to aldehydes and then staining of aldehyles with fuschin–sulfuric acid stains • Predigestion with diastase removes glycogen from sections, leaving other neutral mucopolysaccharides behind

PAS Uses • Basement membrane thickness (in lupus erythematosus evaluation) • Detection of fungi • Presence of glycogen in tumor cells (vs. lipid) (Fig. 3.1)

A

B

Fig. 3.1 PAS is useful for highlighting the basement membrane, seen here as normal, (A) and deep fungi (arrow) as in this case of cutaneous blastomycosis (B)

Alcian Blue • Demonstrates presence of acid mucopolysaccharides • Staining procedure done at pH 2.5 and 0.5 • Positive stain is blue

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• Sulfated mucopolysaccharides (chondroitin sulfate and heparan sulfate) will stain at both pHs, but non sulfated ones only stain at pH 2.5 • Hyaluronic acid is most common non sulfated mucopolysaccharide in skin • Sialomucin produced in extramammary Paget’s disease is also identified with alcian blue • Colloidal Fe essentially indistinguishable staining profile and functions – each lab will have its own preference related to quality of results obtained

Alcian Blue/Colloidal Iron Uses • Detecting mucin in – – – – – – – –

Granuloma annulare Lupus erythematosus Dermatomyositis Scleromyxedema Pre tibial myxedema Scleredema Follicular mucinosis Focal dermal mucinosis (Fig. 3.2)

Elastic von Gieson • A silver stain • Used for demonstration and evaluation of quantity and quality of elastic tissue fibers • Elastic fibers stain black

Von Gieson Uses • To detect elastolysis in – Annular elastolytic granuloma

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Special Stains in Dermatopathology

B

Fig. 3.2 Interstitial mucin may not be apparent on routinely stained sections (A). Alcian blue is used to enhance its visibility in this case of cutaneous mucinosis (B)

– Anetoderma – Cutis laxa • To detect anomalous distribution in – Collagenoma

Brown and Brenn Stain • Tissue gram stain • Used to identify presence of and staining characteristics of bacteria in tissue sections • Can distinguish gram positive and gram negative and cocci and rods • Very difficult to interpret in skin • Cultures are far more sensitive and reproducible

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Acid Fast Stain (AFB) • Good stain for Mycobacterium tuberculosis, but not all atypical mycobacteria • Stains thick wall of organisms • Positive stain is red • Stain done by applying strong acid and decolorizing red slide – only “acid fast” organisms retain the color

Fite Stain • • • •

Stains mycobacteria Much more sensitive for Mycobacterium leprosum than is AFB Positive stain is red Difference from AFB is in the strength of the acid used to decolorize the organisms • M. leprosum does not retain red stain with harsh decolorization procedures (Fig. 3.3)

Giemsa • Metachromatic stain • Positive stain is purple • Used for detecting mast cells (granules are positive). To detect degranulated mast cells, immunohistochemical stains for mast cell surface markers (CD117) are more reliable (see Chapter 4) • Will also stain rickettsial organisms

Giemsa Uses • To detect mast cells in – Urticaria – Mastocytosis/Urticaria pigmentosa

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Fig. 3.3 M. leprosum is more reliably detected with the FIte modification of the acid fast stain

– Leishmaniasis organisms (stain positively) – Donovan bodies in granuloma inguinale (Fig. 3.4)

Warthin-Starry • • • •

Silver nitrate stains spirochetes black Used for detecting organisms in syphilis, Lyme disease Donovan bodies Very difficult to interpret in skin secondary to black staining by melanin granules and elastic tissue fibers in many cases • Usually supplanted by antibody stains and/or serologies (Fig. 3.5)

Masson’s Trichrome

Fig. 3.4 stain

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Mast cell granules stain purple using the Giemsa metachromatic

Masson’s Trichrome • Connective tissue stain used to identify and evaluate characteristics of various connective tissues. This has largely fallen into disuse in recent years with the ease and utility of immunohistochemical stains. – Smooth muscle stains pink – Collagen stains blue-green • Uses – Distinguish leiomyoma vs. neural tumor – Evaluate characteristics of collagen in dermis in collagenoma

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Fig. 3.5 Warthin-Starry detects a spirochete (arrow) in the advancing border of lyme associated erythema chronicum migrans

Congo Red • Used to detect presence of amyloid – Stains red-pink under normal transmitted light – Stains apple green color under polarized light

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– Crystal violet, thioflavin T, and sirius red are also used to detect amyloid but are less convenient and less widely available • Also will stain elastotic material in colloid milium and degenerating keratinocytes in lichen amyloidosis (hence name) (Fig. 3.6)

A

B

Fig. 3.6 Congo Red stains this amyloid deposition red under transmitted light (A) and “apple green” with red birefringence under polarized light (B)

Fontana Stain for Melanin • Silver stain – relies on reduction of silver to form a black precipitate • Used to identify presence of melanin pigment • Evaluation of vitiligo • Distinction between iron and melanin as a source of pigment within macrophages • Identify characteristics of dermal pigmentation secondary to some drug exposures (Fig. 3.7)

Chloroacetate Esterase • Used to identify specific granules in myeloid cells – stains bright red color • Useful for work-up of malignant hematopoietic infiltrates to determine myeloid lineage • Also stains mast cell granules (Fig. 3.8)

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B

Fig. 3.7 Fontana stain highlights normal basilar melanin and melanin conjugates in this biopsy of minocin pigmentation (A). Fontana also detects loss of basilar melanin as in this example of vitiligo (B), with only a small focus of normal basilar pigmentation (arrow)

A

B

Fig. 3.8 In this poorly differentiated hematopoietic infiltrate (A), chloracetate esterase staining (red) characterizes this as myeloid (B)

Perls • Used to detect tissue iron by reacting ferric ions, which are released from tissue with a dilute hydrochloric acid stain, with potassium ferrocyanide, to form a blue precipitate (the Prussian Blue reaction)

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• Useful for identifying iron as the source of pigment in, for example, traumatic nail or dermal pigmentation secondary to medication. • Dermal iron pigmentation in iron overload as in hemochromatosis or repeated red blood cell transfusions. (Fig. 3.9)

A

B

Fig. 3.9 Perl’s iron stain is used to identify the iron chelates, in this case of minocin pigmentation (A) and to highlight the hemosiderin in this case of stasis dermatitis (B)

Chapter 4

Immunopathology in Diagnostic Dermatopathology

Tool Box: Antibody Panel What Is a Tool Box? • Panel of antibodies required to answer a specific question not readily apparent with routine sections (1) (2) (3) (4)

Epithelial markers Mesenchymal markers Neuroectodermal markers Hematopoietic markers (mesenchymal subset)

Epithelial Markers (1) Cytokeratins: These are broadly classified as acidic (type I) and basic to neutral (type II). Type I molecules pair with type II molecules • Numerous keratins of the hair follicle, hair shaft and nail have been identified, but have not yet established themselves at the diagnostic dermatopathology microscope.

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Fig. 4.1 Pan cytokeratin markers (AE1-AE3) are good markers in a broad spectrum panel to screen for cells of epithelial origin. As in this example of squamous cell carcinoma, all levels of the epidermis should stain

(2) Pan-cytokeratin – screen for epithelial origin (Fig. 4.1) (3) CK 5/6 – Type II keratin 5 pairs with type I keratin 14. They, along with keratin pair 6/16, are located in keratinocytes of stratified squamous epithelia, predominantly in the basilar layer. Recognition of keratin 5 and 6 is useful for confirming identification of spindle cell squamous cell carcinomas (sarcomatoid squamous cell carcinoma) (Fig. 4.2) (4) CK 7 – found in simple epithelia, such as duct lining; pairs with keratin 19. It is useful to detect ductular differentiation and in Paget’s disease work-up (Fig. 4.3) (5) CK 20 – useful to identify simple epithelia and Merkel cells in the skin. (Fig. 4.4) (6) CAM5.2 – recognizes low molecular weight keratins 8 and 18 and is of little additional use in the skin (good confirmatory secondary antibody) (7) AE1-AE3 is a keratin antibody cocktail recognizing all except 9,12,17 and 18

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Fig. 4.2 Cytokeratin 5/6 is most prevalent in the basilar epithelial layers, as seen in this section of normal skin

Fig. 4.3 Cytokeratin 7 is useful for identifying simple epithelia such as this eccrine duct lining

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A

B

Fig. 4.4 The cells in this merkel cell carcinoma (A) diffusely express cytokeratin 20 (B)

(8) CEA – largely supplanted by CK7 and EMA (9) Epithelial membrane antigen (EMA) – detects eclectic range of processes including Paget’s disease cells (10) p63 – epithelial transcription factor. Useful in identifying sarcomatoid squamous cell carcinoma from other dermal spindle cell neoplasms. In particular, atypical fibroxanthoma, which would not express p63 while a poorly differentiated squamous cell carcinoma, will. (Fig. 4.5)

A

B

Fig. 4.5 p53 is normally expressed in the basilar epithelium (A). It can be very helpful in identifying epithelial-derived neoplasms such as this squamous cell carcinoma which did not express cytokeratins (B)

Mesenchymal Markers • CD31 – good endothelial cell marker • CD34 – stains endothelial cells, also DFSP (Fig. 4.6)

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Fig. 4.6 CD34 is a good endothelial marker as seen here in this dermatofibroma, which is negative; in the histologic differential diagnosis is a dermatofibrosarcoma protuberans, which would express CD34

• Factor XIIIa – stains dermal dendrocytes and dermatofibroma (Fig. 4.7) • Smooth muscle actin – identifies smooth muscle around blood vessels and arrector pili muscles • Of lesser use in diagnostic dermatopathology: • Desmin • Muscle specific actin (1)

MSA is expressed in dermatomyofibroma

• Of virtually no use in diagnostic dermatopathology: • Vimentin

Neuroectodermal Markers • S100 • MART-1

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Fig. 4.7 Factor XIIIa stains dermal dendrocytes as in this biopsy. It will also be expressed in dermatofibroma

• HMB-45 – Similar staining qualities to MART-1. It is good to have one, but not necessarily both antibodies; this depends on which one works best in the lab performing the stain • Tyrosinase • Micro-ophthalmia transcription factor • Cocktail, including several of above • (Figs. 4.8 and 4.9)

Hematopoietic Markers

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A

B

C

Fig. 4.8 On occasion, the increased basilar pigmentation and the increased single melanocytes of a solar lentigo (A) make differentiation from a primary melanocytic neoplasm difficult. Highlighting the melanocytes with markers can be helpful. Mart-1 and HMB45 (B) are both cytoplasmic markers that can be difficult to interpret due to staining of their elongated processes. Mitf (C) is a nuclear marker that does not have the confounding effect of staining of the dendritic processes and allows for more accurate evaluation of the extent of melanocytic proliferation

Hematopoietic Markers The work-up needed to diagnose hematopoietic neoplasms is beyond the scope of this book. Suffice it to say that all the antigens listed below can be detected in formalin-fixed paraffin-embedded tissue

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Fig. 4.9 Antibodies to S-100 are helpful in delineating the extent of a melanocytic proliferation. It is a cytoplasmic marker that outlines the dendritic processes as well. It will also stain the intraepidermal Langerhans cells, which makes this not as useful a marker as HMB45 or Mart 1 for elaborating melanocytes in a questionable melanoma specimen

• • • • • • • • • • • • • • •

CD1a CD3 CD4 (CD5) (CD7) CD8 CD10 CD20 CD30 CD34 CD43 CD68 CD79a CD99 CD117 – a surface marker for mast cells that stains even if all the cells have degranulated

Hematopoietic Markers

• • • • • • • •

83

CD138 Bcl-2 Bcl-6 (Leukocyte common antigen) (MIB-1/Ki-67/PCNA) Kappa Lambda Figs. 4.10–4.12

A

B

Fig. 4.10 The immunohistochemical evaluation of this cutaneous hematopoietic infiltrate revealed nearly exclusively B-cells, which are CD20+ (A) and kappa restricted with a high proliferative rate as indicated by Ki-67 expression (B)

A

B

Fig. 4.11 Evaluation of this monotonous infiltrate of large cells (A) shows diffuse expression of CD30 (B), helping to characterize this as a large cell lymphoma

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Fig. 4.12 CD117, a surface antigen on mast cells, is useful in this mastocytoma and helpful even if all the cells have degranulated

Miscellaneous Markers • Thyroid transcription factor-1 (TTF-1) helpful in differentiating a primary cutaneous neuroendocrine neoplasm, which typically are negative, from cutaneous metastasis of small cell carcinoma of the lung, which typically is positive • Prostate specific antigen (PSA)/Prostatic alkaline phosphatase (PAP) • Estrogen receptor (ER)/Progesterone receptor (PR)/Androgen receptor (AR) • Anti-spirochete antibodies (Fig. 4.13) • Anti-herpes antibodies • Proliferation markers – Ki-67 – helpful in determining the proliferation index in atypical melanocytic lesions that – MiB1 – used essentially the same as Ki-67 – (Fig. 4.14)

Requirements for Interpretation

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Fig. 4.13 Antibodies to spirochetes, which recognize both borellia spp and syphilis, are sensitive and much easier to interpret than are the classic silver stains such as Warthin Starry (Fig. 3.5), with all the associated problems of excess silver deposition on the slides and confounding background staining of elastic fibers and hematopoietic cells

Requirements for Interpretation • Normal anatomic structures react as expected • Structures that should label with an antibody must do so • Structures that should not label with an antibody must not do so • Without these requirements, correct interpretation is impossible and meaningless! • It is also ESSENTIAL that the interpreter be fully aware of the normal staining pattern, as well as any aberrant staining qualities of every antibody in the tool box in order to prevent misinterpretation (Fig. 4.15)

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Fig. 4.14 Despite unusual architecture and a poorly established pattern of maturation, the low Ki-67 activity in this melanocytic lesion helped determine it’s benignity

Pitfalls in Interpretation Excess immunostaining

Potential solutions

• Tissue dried • Excessive digestion with enzymes • Edge effect • Antibodies too concentrated (1◦ or 2◦ ) • DAB too concentrated

• Redo keeping wet • Decrease incubation time with enzymes • Avoid edges for interpretation • Decrease antibody concentrations or incubation times • Decrease DAB concentration or incubation times • Avoid areas of necrosis for interpretation • Increase blocking time • Compensate with concentrations or incubation times • Unreliable Interpretation

• Tissue necrosis • Non-specific binding • Overfixation • Tissue dried

Strategy for Immunopathology

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Fig. 4.15 As much as possible, internal controls should be used to assess staining adequacy. This case of invasive squamous cell carcinoma was originally diagnosed as an atypical fibroxanthoma because of the lack of cytokeratin expression. Note that the basilar epithelium is not staining with the antibody used. Repeat staining with good internal controls is shown in Fig. 4.1

Insufficient immunostaining

Potential solution

• Old sections – deteriorated antigens • Overfixation • Old antibodies • Too dilute antibodies

• Increase incubation with enzymes

• Need antigen retrieval • Too dilute DAB

• Test with vimentin • Vary concentrations of antibodies • May be required (even if not stated on accompanying literature • Increase DAB concentration

Strategy for Immunopathology • Formulate a specific question to be answered • Construct a panel of antibodies including relevant markers that will support (positive) and refute (negative) entities in the differential diagnosis

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• REMEMBER: immunostains cannot distinguish benign from malignant – they serve to identify differentiation characteristics of cell populations

Immunopathology • Sample panels The following sections depict a series of sample diagnostic dilemmas and the immunostaining profiles that might be used to distinguish between histologically similar entities (Tables 4.1–4.9). • Nota bene: • + means USUALLY, not ALWAYS • − means USUALLY NOT, not NEVER

Table 4.1 Spindle cell neoplasm differential diagnosis

Melanoma AFX SCC Leiomyoma Angiosarcoma

S100

CD68

SMA

MART-1

CK5/6

CD31

p63

+ − − − −

± + − − −

− ± − + −

± − − − −

− − ± − −

− − − − +

− − + − −

AFX = atypical fibroxanthoma, SCC = squamous cell carcinoma

Table 4.2 Pagetoid cell differential diagnosis

Pagets SCCIS Melanoma Eccrine porocarcinoma Sebaceous carcinoma

S100

CK7

AE1/AE3

EMA

MART-1

± − + ± −

+ − − + +

+ + − + −

+ ± − + +

− − + − −

Immunopathology

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Table 4.3 Small blue cell tumor differential diagnosis

TTF-1 Merkel cell − carcinoma Basal cell − carcinoma Metastalic + neuroendocrine carcinoma Primitive − neuroectodermal tumor

Bombesin/ chromogranin/ synaptophysin

CAM5.2

CK20

CD99

+

+

+

−

−

−

−

−

+

+

±

−

−

−

−

+

Table 4.4 Spongiotic dermatitis differential diagnosis

LCH Spongiotic dermatitis Melanoma

CD1a

CD3

CD4

S100

CD68

+ Scattered −

− + −

+ + −

+ − +

+ + ±

LCH = Langerhans cell histiocytocis

Table 4.5 Malignant spindle cell neoplasm differential diagnosis

Angiosarcoma Leiomyosarcoma Melanoma AFX Spindled SCC

CD31

CK5/6

SMA

CD68

S100

p63

+ − − − −

− − − − +

− + − ± −

− ± ± ± −

− − + − +

− − − − +

AFX = atypical fibroxanthoma, SCC = squamous cell Note: Vimentin is not on this panel

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Table 4.6 Lymphomatoid papulosis (LyP) vs. pityriasis lichenoides et varioliformis acuta (PLEVA) vs. anaplastic large cell lymphoma (ALCL)

PLEVA LyP ALCL

CD3

CD4

CD8

CD30

+ + +

Majority Majority Often absent

Minority Minority Often absent

Rare 10–20% >75%

Table 4.7 Dermatofibroma vs. dermatofibrosarcoma protuberans

Dermatofibroma Dermatofibrosarcoma protberans

Factor Xllla

CD34

+ −

− +

Table 4.8 Epithelioid spitz nevus vs. reticulohistiocytoma vs. epitheloid histiocytoma

Epithelioid Spitznevus Epithelioid cell histiocytoma Reticulohistiocytoma

S100

CD68

CD1a

+ Rare + Rare +

± + +

− − −

Table 4.9 Cutaneous Lymphoid Hyperplasia vs. B cell lymphoma

Cutaneous Lymphoid Hyperplasia B Cell Lymphoma

CD3

CD79a

CD68

+ except in germinal centers minority

+ in + diffusely germinal centers + in nodules Absent in and nodular diffusely areas

CD10/bc 1-6/bcl-2 Bcl-2 neg except T cells Bcl-2rarely +, CD10 and bcl-6 often +

Immunopathology

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Closing thoughts: • Sometimes, it isn’t a tumor you are trying to identify – To rule out vitiligo: • Look for loss of melanocytes in the epidermis • S100 staining is confounded by Langerhans cells • MART-1, HMB-45 or MITF are superior • To look for mast cells in the dermis: – C-Kit (CD117) gives a cleaner and stronger signal: noise ratio than Giemsa and has the benefit of being a surface marker, not a marker relying on the presence of intracellular granules • For plasma cells: – CD138 is superior to any prior markers • Cell of origin is the constant in all of this – This is not a benign/malignant paradigm! – The toolbox needs to be in constant evolution – • Consider new “tools” as they may be superior • These “tools” perform differently in each lab and for each diagnostician. Ultimately, you must consider what you are most comfortable with.

Chapter 5

Differential Diagnosis of Normal Skin

Table 5.1 Partial differential diagnosis Amyloidosis Anetoderma Caf´e-au-lait macule Connective tissue nevus Erythrasma Ichthyosis Nephrogenic systemic fibrosis Pemphigus foliaceus/erythematosus Parapsoriasis Pre-tibial myxedema Scleredema Scleromyxedema Tinea versicolor Urticaria Urticaria pigmentosa Vitiligo Wrinkling due to mid-dermal elastolysis

Memorization of an alphabetical list is difficult and not inherently obvious. A superior method for considering diagnostic entities with subtle histologic changes is to develop a systematic plan for reviewing all skin biopsies.

B.R. Smoller, K.M. Hiatt, Dermatopathology: The Basics, DOI 10.1007/978-1-4419-0024-1 5,  C Springer Science+Business Media, LLC 2009

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Differential Diagnosis of Normal Skin

• Strategy – Systematically review each anatomic layer of the skin (see Chapter 1) – Specifically detect subtle lesions that may be present at each level • Subtle Alterations in the Stratum Corneum – Tinea versicolor – Ichthyosis • X-linked • Lamellar • Erythrasma

Tinea Versicolor • Caused by Pityrosporum versicolor • Scaly, erythematous to red-brown annular lesions • Can occur anywhere on body (head and neck less common in adults) • Often very pruritic • Histologic findings – Small foci of parakeratotic keratin – Minimal superficial perivascular inflammation (occasionally eosinophils or neutrophils may be present) – Mild spongiosis – PASD stains often helpful in making diagnosis – neutrophils in the stratum corneum may be a hint to requesting a PASD stain (Figs. 5.1–5.3)

Tinea Versicolor

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Fig. 5.1 The low magnificiaton for tinea versicolor strongly resembles a biopsy of normal skin (×40)

Fig. 5.2 Higher magnification demonstrates yeast and hyphal forms of fungi in some preparations (×400)

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Differential Diagnosis of Normal Skin

Fig. 5.3 A PASD stain demonstrates hyphal and yeast forms within the stratum cornuem, often adjacent to areas of parakeratosis (×600)

Ichthyoses • Multiple types with varying inheritance patterns • Some are hyperproliferative states, others are caused by retention phenomena • Many syndromes associated with different ichthyoses • Only some forms demonstrate minimal changes in stratum corneum – most subtypes demonstrate extensive histologic alterations and would not be confused with normal skin

Ichthyosis (X-Linked) • Histologic findings – Stratum corneum demonstrates compact hyperkeratosis with minimal to no parakeratosis – Minimal hyperkeratosis in X-linked (more closely resembles normal skin than any other type of ichthyosis)

Ichthyosis (Lamellar)

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– Epidermis is essentially normal thickness (Fig. 5.4) – Granular layer approximately normal in thickness to mildly thickened – No inflammation present

Fig. 5.4 X-linked ichthyosis is characterized by compact hyperkeratosis and an essentially normal epidermis (×200)

Ichthyosis (Lamellar) • Histologic findings – Less like normal skin than X-linked variant – Markedly thickened compact orthokeratotic keratin (easily overlooked as compacted secondary to rubbing) (Fig. 5.5) – Slightly acanthotic epidermis with hypergranulosis

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Differential Diagnosis of Normal Skin

Fig. 5.5 Lamellar ichthyosis demonstrates a markedly thickened and compact stratum corneum without parakeratosis (×200)

Erythrasma • Caused by Corynebacterium minutissimum (diptheroid) • Well-demarcated red-brown scaly patches in intertriginous areas • Coral red immunofluorescence with Wood’s light examination • Histologic findings – Gram-positive rods and filaments in stratum corneum – Minimal other histologic changes (virtually no inflammatory reaction) (Figs. 5.6 and 5.7)

Erythrasma

99

Fig. 5.6 Small collections of blue-stained structures (bacteria and parakeratotic corneocytes) are present at low magnification in erythrasma (×40)

Fig. 5.7 At higher magnification, bacteria are apparent on routine sections in erythrasma (×400)

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Differential Diagnosis of Normal Skin

• Subtle changes in stratum granulosum – Ichthyosis vulgaris and acquired variant of ichthyosis – Pemphigus foliaceus/erythematosus

Ichthyosis Vulgaris • Acquired variant associated with malignancy, AIDS, sarcoidosis, other systemic processes • Dry, flaky, scaly skin, often on lower extremities – Histologic findings • Absence or marked diminution of granular layer • Difficult to notice this without specific attention to it • Stratum corneum with slightly thickened and compact orthokeratosis (Fig. 5.8) • No parakeratosis • No inflammation

Fig. 5.8 Ichthyosis vulgaris features a subtle loss of the granular layer and thickened, commact orthokeratotic keratin (×200)

Pemphigus Foliaceus/Erythematosus

101

Pemphigus Foliaceus/Erythematosus • Superficial scales predominate over intact blisters • Often on back and chest and scalp • Histologic findings – Stratum corneum and stratum granulosum often not present – separated by blister – Focal acantholysis within stratum granulosum is best clue to diagnosis – Minimal inflammation – No changes in lower epidermis – Minimal inflammation in most cases (Figs. 5.9 and 5.10) • Subtle changes in stratum malpighii – None • Subtle changes in stratum basalis

Fig. 5.9 Pemphgius foliaceus (and erythematosus) demonstrate a very superficial blister. The fragile roof of the blister often completely separates and is lost in processing (×100)

102

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Differential Diagnosis of Normal Skin

Fig. 5.10 Higher magnification depicts acantholysis of the granular layer, giving rise to the very superficial blister in pemphigus foliaceus/erythematosus (×200)

– Vitiligo – Caf´e-au-lait macule – Nevus depigmentosus

Vitiligo • Areas of abrupt total pigment absence • Peri orificial, often symmetrical • Histologic features – Focal loss of melanocytes (Fig. 5.11) – Minimal inflammation – No evidence of post-inflammatory pigment deposition in dermis (few if any dermal melanophages) – Fontana stain helpful in detecting absence of basal layer melanin (Fig. 5.12) – S100 or MART-1 stain demonstrates focal loss of melanocytes

Vitiligo

103

Fig. 5.11 A loss of melanocytes along the basal layer often represents the only evidence of vitiligo on routine histologic sections (×200)

Fig. 5.12 A Fontana stain for melanin is often helpful in making a diagnosis of vitiligo by demonstrating complete absence of basal layer melanin pigment (×200)

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Differential Diagnosis of Normal Skin

Caf´e-Au-Lait Macule • • • •

Occurs in almost all patients with neurofibromatosis Can take up to a year after birth to appear Continue to increase in size and number for up to 2 years More than six lesions exceeding 1.5 cm in diameter is diagnostic of neurofibromatosis • Histologic features (Fig. 5.13) – Increased melanin in keratinocytes and melanocytes (very subtle) – Giant melanin granules – not specific (Fig. 5.14) – Increased density of melanocytes (very minimally increased)

Fig. 5.13 Histologic changes in caf´e-au-lait macule include basilar hyperpigmentation, a slight increase in melanocytes, and rarely giant melanin granules (not seen in this case) (×200)

Nevus Depigmentosus (Nevus Achromicus)

105

Fig. 5.14 Giant melanin granules are sometimes seen in caf´e-au-lait macules, but are not specific (×500)

Nevus Depigmentosus (Nevus Achromicus) • Hypopigmented macule, usually appears at birth or in early childhood • Most common on trunk and extremities • Rarely systematized or linear • Histologic features – Melanocytes normal or minimally decreased – Decreased melanin in basal layer of epidermis (best highlighted with Fontana stain for melanin) • Subtle Alterations in the Dermis – Connective tissue abnormalities – Deposition disorders – Conditions with minimal inflammatory infiltrates

106

5

Differential Diagnosis of Normal Skin

Subtle connective tissue disorders – – – – –

Connective tissue nevus Cutis laxa Morphea/scleroderma Anetoderma Wrinkling due to mid-dermal elastolysis

Connective Tissue Nevus • Hamartoma with increased collagen and altered elastic tissue (can be increased, decreased, or even normal in quantity) (Fig. 5.15) • Elevated, indurated nodules grouped into plaques • Can be autosomal dominant inheritance • Associated with Buschke-Ollendorf syndrome

Fig. 5.15 A connective tissue nevus demonstrates thickened and haphazardly arranged bundles of collagen in the dermis, often with absence of cutaneous appendages (×20)

Connective Tissue Nevus

107

• Shagreen patches in tuberous sclerosis – collagenoma type of connective tissue nevus • Histologic features – Thickened and homogenized collagen bundles (Fig. 5.16) – May see increased or decreased elastic fibers on elastic tissue stain (or pattern somewhat altered) (Fig. 5.17) – Epidermis is normal – No inflammation present

Fig. 5.16 Thickened collagen bundles and decreased intervening ground substance are seen in connective tissue nevi (×40)

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Differential Diagnosis of Normal Skin

Fig. 5.17 An elastic tissue stain (Verhoff van Gieson) demonstrates nearly total absence of elastic tissue fibers in the region of collagen overgrowth in the collagenoma variant of a connective tissue disease (×100)

Cutis Laxa • Also known as generalized elastolysis • Loose, pendulous skin – prematurely aged appearance • Sporadic or inherited (autosomal recessive or less commonly autosomal dominant) • Internal organs involved – diverticula (GI tract and bladder), rectal prolapse, hernias • Can see urticaria or erythematous papules or vesicles • Histologic features – Early – only decrease in elastic fibers in superficial dermis, some thickening of remaining elastic fibers – Later – no intact elastic tissue fibers – Some cases have inflammation, usually with neutrophils, and may resemble dermatitis herpetiformis (Figs. 5.18 and 5.19)

Cutis Laxa

109

Fig. 5.18 Collagen bundles are disordered and widely separated due to loss of elastic tissue in cutis laxa (×400)

Fig. 5.19 Elastic tissue stain demonstrates complete loss of elastic tissue fibers in well-developed lesion of cutis laxa (×400)

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Differential Diagnosis of Normal Skin

Morphea • Many subtypes – overlapping histologic features, distinction is mainly clinical – Guttate, plaque, linear, segmental, subcutaneous (eosinophilic fasciitis), generalized – Guttate type clinically resembles lichen sclerosis et atrophicus – Indurated plaques with smooth, ivory color – Linear on extremities and scalp (coup de sabre) – Segmental – results in hemiatrophy of half of face • Histologic features – Early (inflammatory) thickened collagen and moderately severe inflammation of lympocytes with eosinophils and plasma cells at subcutaneous fat junction and around eccrine glands – Late – dermal collagen thickened, closely packed • No inflammation, normal epidermis, atrophic and trapped eccrine apparatus, loss of other appendages – Scleroderma – histologically identical- distinction made entirely based upon clinical correlation (Figs. 5.20–5.23)

Morphea

111

Fig. 5.20 Early morphea demonstrates an interstitial infiltrate of polymorphous inflammatory cells and slight thickening of collagen with increased edema (×100)

Fig. 5.21 Low magnification demonstrates a dense dermis with thickened collagen and minimal cellularity in well-developed lesions of morphea or scleroderma. Note, also, the entrapped eccrine structures (×40)

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Differential Diagnosis of Normal Skin

Fig. 5.22 Peri-eccrine lymphocytes and plasma cells are characteristic of morpphea/scleroderma, as is pronounced thickening of collagen bundles within the reticular dermis (×200)

Fig. 5.23 Relatively few lesions within the dermis contain the tightly cuffed lymphocytes and plasma cells around vessels and eccrine structures that characterize morphea/scleroderma (×400)

Anetoderma (Macular Atrophy, Focal Dermal Elastolysis)

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Anetoderma (Macular Atrophy, Focal Dermal Elastolysis) • • • • • •

Atrophic patches located on upper trunk Thin, bulging, blue-white skin Palpable with finger as hernia Jadassohn type – initially inflammatory Schweninger-Buzzi type – non inflammatory May be secondary to syphilis, lupus, leprosy, penicillamine therapy • Histologic findings – Early – may see perivascular lymphocyte infiltrate, occasionally with neutrophils and eosinophils – Elastic tissue rapidly decreases – better identified with elastic tissue stain – Late – complete loss of elastic fibers in papillary and upper reticular dermis, no inflammation, normal epidermis (Figs. 5.24 and 5.25)

Fig. 5.24 Wide spaces separating collagen bundles in the superficial reticular dermis are characteristic of anetoderma (×100)

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Differential Diagnosis of Normal Skin

Fig. 5.25 Loss of elastic tissue fibers account for the separated collagen bundles in anetoderma, as seen on this elastic tissue stain (×100)

Wrinkling due to Mid-dermal Elastolysis • Rare • Occurs primarily in middle-aged women • Widespread areas of fine wrinkling with soft papular lesions with indented central hair follicles • Histologic findings – Absence of elastic fibers restricted to mid-dermis – Elastic fibers preserved around hair follicles

Dermal Deposition Disorders • • • • •

Amyloidosis Pretibial myxedema Scleredema Scleromyxedema Nephrogenic systemic fibrosis

Localized Cutaneous Amyloidosis

115

Amyloidosis • Primary systemic and localized amyloidosis can involve the skin • Secondary amyloidosis does NOT involve the skin • Localized has three patterns – Lichen amyloidosis – Macular amyloidosis – Nodular amyloidosis (does not resemble normal skin) • No inflammation • 40% of skin biopsies demonstrate amyloid with primary amyloidosis

Localized Cutaneous Amyloidosis • Lichen amyloidosis – discrete brown-red papules with scaling, often on shins – May become verrucous – Very pruritic • Macular amyloidosis – often on upper back, reticulated pattern, common in SE Asia • Histologic features – Lichen and macular amyloidosis have deposits limited to papillary dermis – Lichen amyloidosis has epidermal hyperplasia not seen in macular amyloidosis (changes secondary to chronic rubbing – identical to changes seen in lichen simplex chronicus) – Eosinophilic amorphous material seen as globules beneath epidermis – Globules in papillary dermis stain with Congo red, crystal violet, anti-keratin antibodies – Amorphous material is actually NOT amyloid, but keratin breakdown products that are similar in size and staining properties to amyloid (Figs. 5.26 and 5.27)

116

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Differential Diagnosis of Normal Skin

Fig. 5.26 Changes of lichen simplex chronicus are present overlying eosinophilic globules in the dermis in lichen amyloidosis (×200)

Fig. 5.27 The eosinophilic globules in lichen amyloidosis are in papillary dermal tips and are derived from degenerating keratinocytes (×400)

Pretibial Myxedema

117

Pretibial Myxedema • • • •

Usually on anterior legs Raised, nodular, waxy plaques Associated with thyrotoxicosis – elevated LATS Histologic features (see Table 2) – Mucin in middle to lower third of dermis – best identified with colloidal iron (or alcian blue) stains performed at pH 2.5 – Normal numbers of fibroblasts (may be stellate) – (as opposed to other dermal mucinoses such as scleromyxedema in which there is a marked increase in dermal fibroblasts) (Figs. 5.28 and 5.29)

Table 5.2 Dermal mucinoses – major points of histologic distinction

Increased fibroblasts Normocellular

Superficial

Deep

1. Scleromyxedema/lichen myxedematosus 2. Pretibial myxedema 1. Pretibial myxedema 2. Idiopathic focal papular mucinosis

1. Nephrogenic systemic fibrosis 2. Pretibial myxedema Scleredema

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Differential Diagnosis of Normal Skin

Fig. 5.28 Pretibial myxedema is characterized by abundant deposition of mucin in the dermis in the absence of significant fibroblastic response (×100)

Fig. 5.29 Collodial iron stain is helpful in demonstrating the pale-staining areas to be composed of acid mucopolysaccharides (mucin) (×100)

Sclerodema

119

Sclerodema • Diffuse, non pitting swelling of skin • Abrupt onset following acute URI, streptococcal infection in some cases • Associated with diabetes in other cases – non reversible • Idiopathic rarely • Involves face, neck, back, upper extremities • 75% resolve within a few years • Histologic features (see Table 2) – Dermis is up to ×3 the normal thickness – Collagen bundles thickened, widely separated by clear spaces (unlike scleroderma) – Eccrine ducts appear to be in upper dermis – No increase in numbers of fibroblasts (as opposed to scleromyxedema) – Colloidal iron/alcian blue demonstrates abundant hyaluronic acid (mucin) (Figs. 5.30 and 5.31)

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Differential Diagnosis of Normal Skin

Fig. 5.30 Scleredema demonstrates thickened collagen bundles in the reticular dermis widely separated by areas with minimal or slightly bluish staining (×100)

Fig. 5.31 Colloidal iron stains demonstrate increased mucin between collagen bundles within the reticular dermis in scleredema (×200)

Scleromyxedema

121

Scleromyxedema • Also known as “papular mucinosis” and lichen myxedematosus • Asymptomatic, soft papules densely grouped • Accentuation of skin folds and thickening of skin with erythema • Lichen myxedematosus is a less extensive variant • Histologic features (see Table 2) – Well-circumscribed deposits of mucin in superficial dermis with increased numbers of fibroblasts – No epidermal changes – Minimal associated inflammatory infiltrate (Figs. 5.32 and 5.33)

Fig. 5.32 An increase in fibroblasts percolating between collagen bundles is seen in the superficial reticular dermis and papillary dermis in scleromyxedema (×100)

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Differential Diagnosis of Normal Skin

Fig. 5.33 Alcian blue stain demonstrates increased mucin between collagen bundles in the upper half of the dermis in scleromyxedema (×100)

Nephrogenic Systemic Fibrosis • Associated with end-stage renal disease • Most patients exposed to gadolinium contrast media for magnetic resonance imaging (MRI) • Sclerotic, thickened extremities resemble scleroderma • Relatively rapid onset • Histologic findings (see Table 2) – Normal epidermis – Increase in dermal fibroblasts coursing in myxoid ground substance – Minimal accompanying lymphoid inflammatory infiltrate – Accumulation of mucin and cells starts in mid-reticular dermis, extends into fibrous septa between adipocyte lobules – Histologically similar to scleromyxedema, but much deeper into dermis and subcutaneous fat – Can be extensive or quite subtle (Figs. 5.34 and 5.35)

Nephrogenic Systemic Fibrosis

123

Fig. 5.34 The superficial dermis demonstrates a subtle increase in fibroblasts coursing between collagen bundles in nephrogenic systemic fibrosis (×100)

Fig. 5.35 Fibrous septa are thickened and also demonstrate increased fibroblastic cellularity in nephrogenic systemic fibrosis (×100)

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Differential Diagnosis of Normal Skin

Conditions with Minimal Inflammation • Parapsoriasis (small plaque, guttate) • Urticaria • Urticaria pigmentosa

Small Plaque (Guttate) Parapsoriasis (Digitate Dermatosis) • Erythematous patches with fine scale on lateral trunk – thumb print sized • Asymptomatic to mildly pruritic • Poorly responsive to topical therapy • Indolent with minimal progression over long periods of time • Histologic features – Small foci of parakeratosis – minimal – Slight spongiosis focally – Minimal perivascular lymphocytic infiltrate with focal exocytosis – Eosinophils not common (Figs. 5.36 and 5.37)

Small Plaque (Guttate) Parapsoriasis (Digitate Dermatosis)

125

Fig. 5.36 Small plaque parapsoriasis is characterized by a slight superficial perivascular lymphocytic infiltrate (×100)

Fig. 5.37 Higher magnification demonstrates focal parakeratosis, focal spongiosis, and minimal exocytosis in small plaque parapsoriasis (digitate dermatosis) (×200)

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Differential Diagnosis of Normal Skin

Urticaria • Transient, recurrent wheals • Usually pruritic • Histologic features – Epidermis entirely normal – Dermal edema with sparse perivascular infiltrate of lymphocytes, neutrophils, eosinophils (Fig. 5.38) – Minimal dermal edema – No vasculitis

Fig. 5.38 A sparse, mixed inflammatory infiltrate is seen around the superficial vascular plexus in urticaria. Slight edema may be present (×200)

Urticaria Pigmentosa • Many variants • Telangiectasia macularis eruptiva perstans – most common adult variant – most similar to normal skin

Urticaria Pigmentosa

127

– Reticulated hyperpigmentation on chest and back of middleaged to elderly patients – Rare to see systemic involvement (unlike some childhood variants of mast cell disease) • Histologic features – Minimal inflammatory infiltrate surrounding vessels of superficial vascular plexus (Fig. 5.39)

Fig. 5.39 At low magnification, urticaria pigmentosa resembles a mild superficial perivascular dermatitis with minimal epidermal change (×100)

– Infiltrate of lymphocytes and mast cells (Fig. 5.40) – Usually requires Giemsa, mast cell tryptase, or CD117 to identify mast cells (Fig. 5.41) – Subtle increase in mast cells in TMEP (other forms of cutaneous mast cell disease, i.e., mastocytoma, have much more extensive infiltrates of mast cells within the dermis)

128

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Differential Diagnosis of Normal Skin

Fig. 5.40 High magnification of urticaria pigmentosa demonstrates perivascular cells with eosinophilic cytoplasm, suggestive of mast cells opposed to lymhocytes (×600)

Fig. 5.41 Giemsa stain demonstrates metachromatic granules in the cytoplasm of mast cells in urticaria pigmentosa (×400)

Further Reading

Chapter 1 Keratinocytes Klein-Sznto AJP, Barr RJ, Reiners JJ, Mamrack MD. Filaggrin distribution in keratoacanthomas and squamous cell carcinoma. Arch Pathol Lab Med 1984; 108: 888–890. Leigh IM, Purkis PE, Whitehead P, Lane EB. Monospecific monoclonal antibodies to keratin 1 terminal (synthetic peptide) and to keratin 10 as markers of epidermal differentiation. Br J Dermatol 1993; 129: 110–119. Smack DP, Korge BP, James WD. Keratin and keratinization. J Am Acad Dermatol 1994; 30: 85–102. Sun T-T, Eichner R, Nelson WG, Tseng SCG, Weiss RA, Jarvinen M, Woodcock-Mitchell J. Keratin classes: molecular markers for different types of epithelial differentiation. J Invest Dermatol 1983; 81: 09s–115s. Thacher SM, Rice RH. Keratinocyte-specific transglutaminase of cultured epidermal cells: relation to cross-linked envelope formation and terminal differentiation. Cell 1985; 40: 685–695. Woodcock-Mitchell J, Eichner R, Nelson WC, Sun T-T. Immunolocalization of keratin polypeptides in human epidermis using monoclonal antibodies. J Cell Biol 1982; 95: 580–588.

Melanocytes Fitzpatrick TB, Szabo G. The melanocyte: Cytology and cytochemistry. J Invest Dermatol 1959; 32: 197–209. Mooi WJ, Krausz T. Melanin and melanocytes, in Mooi WJ, Krausz T (eds): Biopsy Pathology of Melanocytic Disorders. London, Chapman and Hall, 1991, pp. 1–16.

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Prota G, Nicolaus RA. On the biogenesis of phaeomelanins, in Montagna W, Hu F (eds): Advances in Biology of Skin. New York, Pergamon Press, 1966, pp. 323–328. Szabo G, Gerald AB, Pathak MA, Fitzpatrick TB. Racial differences in human pigmentation at the ultrastructural level. J Cell Biol 1968; 39: 132–133.

Langerhans Cells Burkert KL, Huhn K, Menezes DW and Murphy GF. Langerhans cell microgranulomas (pseudo-pautrier abscesses): morphologic diversity, diagnostic implications and pathogenetic mechanisms. J Cutan Pathol 2002; 29: 511–516. Horton JJ, Allen MH, MacDonald DM. An assessment of Langerhans cell quanitification in tissue sections. J Am Acad Dermatol 1984; 11: 591–593. Murphy GF. Cell membrane glycoprotein’s and Langerhans cells. Hum Pathol 1985; 16: 103–112. Moresi JMM, Horn TD. Distribution of Langerhans cells in human hair follicle. J Cutan Pathol 1997; 24: 636–640. Thorbecke GJ, Silberberg-Sinakin I, Flotte TJ. Langerhans cells as macrophages in skin and lymphoid organs. J Invest Dermatol 1980; 75: 32–43. Toews GB, Bergstresser PR, Streilein JW. Langerhans cells: sentinels of skin associated lymphoid tissue. J Invest Dermatol 1980; 75: 78–82.

Merkel Cells Boot PM, Rowden G, Walsh N. The distribution of Merkel cells in human fetal and adult skin. Am J Dermatopathol 1992; 14: 391–396. Moll I, Kuhn C, Moll R. Cytokeratin 20 is a general marker of cutaneous Merkel cells while certain neuronal proteins are absent. J Invest Dermatol 1995; 104: 910–915. Ratner D, Nelson BR, Brown MD, Johnson TM. Merkel cell carcinoma. J Am Acad Dermatol 1993; 29: 143–156.

Cutaneous Appendages Headington JT. Transverse microscopic anatomy of the human scalp. A basis for a morphometric approach to disorders of the hair follicle. Arch Dermatol 1984; 120: 449–456.

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Kligman AM. The human hair cycle. J Invest Dermatol 1959; 33: 307–316. Montagna W, Chase HB, Lobitz WC Jr. Histology and cytochemistry of human skin: IV. The eccrine sweat glands. J Invest Dermatol 1953; 20: 415–423. Olsen EA. Disorders of Hair Growth: Diagnosis and Treatment. New York, McGraw Hill, 1994. Whiting DA. Diagnostic and predictive value of horizontal sections of scalp biopsy specimens in male pattern androgenetic alopecia. J Am Acad Dermatol 1993; 28: 755–763.

Basement Membrane Zone Eady RAJ. The basement membrane. Arch Dermatol 1988; 124: 709–712. Eady RAJ. Babes, blisters and basement membranes: From sticky molecules to epidermolysis bullosa. Clin Exp Dermatol 1987; 12: 161–170.

Chapter 2 Cassarino DS, Derienzo DP, Barr RJ. Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification—part two. J Cutan Pathol 2006; 33: 261–279. De Jong MC, Bruins S, Heeres K, et al. Bullous pemphigoid and epidermolysis bullosa acquisita. Differentiation by fluorescence overlay antigen mapping. Arch Dermatol 1996; 132: 151–157. Delendi M, Puglisi F, Della Mea V, Riberti C, Osti M, Parodi PC. Spiradenocarcinoma: morphological and immunohistochemical features. Adv Clin Path 1997; 1: 287–291. Jordan RE. Immunologic Diseases of the Skin. Norwalk, Appleton and Lange, 1991. Ko JC, Cochran AJ, Eng W, Binder SW. Hidradenocarcinoma: a histological and immunohistochemical study. J Cutan Pathol 2006; 33: 726–730. Laochumroonvorapong P, Kokta V, Quan MB. Trichilemmal carcinoma in an African American. Dermatol Surg 2002; 28: 284–286. Liegl B, Leibl S, Okcu M, Beham-Schmid C, Regauer S. Malignant transformation within benign adnexal skin tumours. Histopathology 2004; 45: 162–170. Sugai SA, Gerbase AB, Cernea SS, et al. Cutaneous lupus erythematosus: direct immunofluorescence and epidermal basal membrane study. Int J Dermatol 1992; 31: 260–264. Vodegel RM, de Jong MC, Meijer HJ, Weytingh MB, Pas HH, Jonkman MF. Enhanced diagnostic immunofluorescence using biopsies transported in saline. BMC Dermatol 2004; 4: 10.

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Vogelbruch M, Rutten A, Bocking A, Kapp A, Kiehl P. Differentiation between malignant and benign follicular adnexal tumours of the skin by DNA image cytometry. Br J Dermatol 2002; 146: 238–243. Wilkerson AE, KM H. Get better pathology results: Advice from a dermatopathologist. Pract Dermatol 2004; 1: 32.

Chapter 3 Berger BW. Dermatologic manifestations of Lyme disease. Rev Infect Dis 1989; 11 Suppl 6: S1475–1481. Berger BW, Clemmensen OJ, et al. Lyme disease is a spirochetosis: a review of the disease and evidence for its cause. Am J Dermatopathol 1983; 5(2): 111–124. Bond JS, Duncan JA, et al. Maturation of the human scar: an observational study. Plast Reconstr Surg 2008; 121(5): 1650–1658. Helm KF, Goellner JR, et al. Immunohistochemical stains in extramammary Paget’s disease. Am J Dermatopathol 1992; 14(5): 402–407. Igarashi M, Aizawa H, et al. Dermatomyositis with prominent mucinous skin change: histochemical and biochemical aspects of glycosaminoglycans. Dermatologica 1985; 170(1): 6–11. Kuhn A, Sonntag M, et al. Histopathologic findings in lupus erythematosus tumidus: review of 80 patients. J Am Acad Dermatol 2003; 48(6): 901–908. Kupchella CE, Matsuoka LY, et al. Histochemical evaluation of glycosaminoglycan deposition in the skin. J Histochem Cytochem 1984; 32(10): 1121–1124. Majzoub M, Breuer W, et al. Histopathologic and immunophenotypic characterization of extramedullary plasmacytomas in nine cats. Vet Pathol 2003; 40(3): 249–253. Reed SB and Morris GT. Amyloidosis: current approaches for diagnosis and treatment. J Ky Med Assoc 1992; 90(2): 68–72. Salim T, Shenoi SD, et al. Lichen amyloidosus: a study of clinical, histopathologic and immunofluorescence findings in 30 cases. Indian J Dermatol Venereol Leprol 2005; 71(3): 166–169. Steigleder GK and Kuchmeister B. Cutaneous mucinous deposits. J Cutan Pathol 1985; 12(3–4): 334–347. Stevens A, Bancroft JD (eds). Theory and Practice of Histologic Techniques. Ediburgh, Churchill Livingstone, 1990. Suster S. Hyalinizing spindle and epithelioid cell nevus: a study of five cases of a distinctive histologic variant of Spitz’s nevus. Am J Dermatopathol 1994; 16(6): 593–598. Thyresson HN and Su WP. Familial cutaneous leiomyomatosis. J Am Acad Dermatol 1981; 4(4): 430–434.

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Chapter 4 Candi E, Cipollone R, et al. p63 in epithelial development. Cell Mol Life Sci 2008; 65(20): 3126–3133. Di Como CJ, Urist MJ, et al. p63 expression profiles in human normal and tumor tissues. Clin Cancer Res 2002; 8(2): 494–501. Folpe AL and Cooper K. Best practices in diagnostic immunohistochemistry: pleomorphic cutaneous spindle cell tumors. Arch Pathol Lab Med. 2007; 131(10): 1517–1524. Gown AM, de Wever N, Battifora H. Microwave-based antigenic unmasking: a revolutionary new technique for routine immunohistochemisty. Appl Immunohistochemistry 1993; 1: 256–266. Moll R, Divo M, et al. The human keratins: biology and pathology. Histochem Cell Biol 2008; 129(6): 705–733. Nadji M, Morales AR. Immunoperoxidase, Part 1. The technique and its pitfalls. Lab Med 1983; 14: 767–771. O’Reilly FM, Brat DJ, McAlpine BE, Grossniklaus HE, Folpe AL and Arbiser JL. Microphthalmia transcription factor immunohistochemistry: a useful diagnostic marker in the diagnosis and detection of cutaneous melanoma, sentinel lymph node metastases and extracutaneous melanocytic neoplasms. J Am Acad Dermatol 2001; 45(3): 414–419. Pellegrini G, Dellambra E, et al. p63 identifies keratinocyte stem cells. Proc Natl Acad Sci USA 2001; 98(6): 3156–3161. Plumb SJ, Argenyi ZB, Stone MS and DeYoung BR. Cytokeratin 5/6 immunostaining in cutaneous adnexal neoplasms and metastatic adenocarcinoma. Am J Dermatopathol 2004; 26(6): 447–451. Smoller BR. Practical Immunopathology of the Skin. Totowa, Humana Press, 2002. Taylor CR, Chir B. Immunoperoxidase tehcniques. Practical and theoretical aspects. Arch Pathol Lab Med 1978; 102: 113–121. Tsujita-Kyutoku M, Kiuchi K, et al. p63 expression in normal human epidermis and epidermal appendages and their tumors. J Cutan Pathol 2003; 30(1): 11–17. Wallace ML, Smoller BR. Immunohistochemistry in diagnostic dermatopathology. J Am Acad Dermatol 1996; 34: 163–183.

Chapter 5 Tinea Versicolor Lesher JL Jr. An Atlas of Micobiology of the Skin. New York, Parthenon, 2000. Svejgaard E. Epidemiology and clinical features of dermatomycoses and dermatophytoses. Acta Derm Venereol (Stockh), 1986; 121: suppl. 119–26.

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Ichthyosis Patel N, Spencer LA, English JC III, Zirwas MJ. Acquired ichthyosis. J Am Acad Dermatol 2006; 55: 647–656. Rand RE, Baden HP. The ichthyoses: a review. J Am Acad Dermatol 1983; 8: 285–305. Scheimberg I, Harper JI, Malone M, Lake BD. Inherited ichthyoses: a review of the histology of the skin. Pediatr Pathol Lab Med 1996; 16: 359–378.

Erythrasma Lesher JL Jr. An Atlas of Micobiology of the Skin. New York, Parthenon, 2000.

Pemphigus Foliaceus/Erythematosus Diaz LA, Sampaio SA, Rivitii EA, Martins CR, Cunha PR, Lombardi C, Almeida FA, Castro RM, Macca ML, Lavrado C, et al. Endemic pemphigus foliaceus (fogo selvagem). I. Cinical features and Immunopathology. J Am Acad Dermatol 1989; 20: 657–669. Korman N. Pemphigus. J Am Acad Dermatol 1988; 18: 1219–1238. Metry DW, Hebert AA, Jordon RE. Nonendemic pemphigus foliaceus in children. J Am Acad Dermatol 2002 ;46: 419–422.

Vitiligo Kovacs SO. Vitiligo. J Am Acad Dermatol 1998; 38: 647–666. Sharquiet KE, Mehenna SH, Naji AA, Al-Azzawi H. Inflammatory changes in vitiligo. Stage I and II depigmentation. Am J Dermatopathol 2004; 26: 108–112.

Caf´e-au-lait Macule Jimbow K, Szabo G, Fitzpatrick TB. Ultrastructure of giant pigment granules (macromelanosomes) in the cutaneous pigmented macules of neurofibromatosis. J Invest Dermatol 1973; 61: 300–309.

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Connective Tissue Nevus Rocha G, Winkelmann RK. Connective tissue nevus. Arch Dermatol 1962; 85: 78–85. Smith LR, Bernstein BD. Eruptive collagenoma. Arch Dermatol 1978; 114: 1710–1711. Trau H, Dayan D, Hirschberg A, Hiss Y, Bubis JJ, Wolman M. Connective tissue nevi collagens: Study with picrosirius red and polarizing microscopy. Am J Dermatopathol 1991; 13: 374–377.

Cutis Laxa Lewis KG, Bercovitch L, Dill SW, Robinson-Boston L. Acquired disorders of elastic tissue. Part II: decreased elastic tissue. J Am Acad Dermatol 2004; 51: 165–185. Uitto J, Shamban A. Heritable skin diseases with molecular defects in collagen or elastin. Dermatol Clin 1987; 5: 63–84.

Scleroderma/Morphea Livingston JZ, Scott TE, Wigley FM, Anhalt GJ, Bias WB, McLean RH, Hochberg MC. Systemic sclerosis (scleroderma): clinical, genetic and serologic subsets. J Rheumatol 1987; 14: 512–518. McNiff JM, Glusac EJ, Lazova RZ. Morphea limited to the superficial reticular dermis: an unrecognized histologic phenomenon. Am J Dermatopathol 1999; 21: 315–319. Perez ML, Kohn SR. Systemic sclerosis. J Am Acad Dermatol 1993; 28: 525–547.

Anetoderma Hodak Em, Shamai-Lubovitz O, David M, Hazaz B, Lahav M, Sandbank M. Primary anetoderma associated with a wide spectrum of autoimmune abnormalities. J Am ACad Dermatol 1991; 25: 415–418. Venencie PY, Winkelmann RK. Histopathologic findings in anetoderma. Arch Dermatol 1984; 120: 1040–1044. Venencie PY, Winkelmann RK, Moore BA. Anetoderma: clinical findings, associations, and long-term follow-up evaluations. Arch Dermatol 1984; 120: 1032–1039.

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Wrinkling due to Mid-dermal Elastolysis Agha A, Hashimoto K, Mahon M. Mid-dermal elastolysis: case report and review of the literature. J Dermatol 1994; 21: 760–766. Rao BK, Endzweig CH, Kagen MH, Kriegel D, Freeman RG. Wrinkling due to mid-dermal elastolysis: two cases and literature review. J Cutan Med Surg 2000; 4: 40–44.

Amyloidosis Breathnach SM. The cutaneous amyloidoses. Arch Dermatol 1985; 121: 470–475. Breathnach SM. Amyloid and amyloidosis. J Am Acad Dermatol 1988; 18: 1–16. Touart DM, Sau P. Cutaneous deposition diseases. Part I. J Am Acad Dermatol 1998; 39: 149–171.

Pre-tibial Myxedema Jabbour SA. Cutaneous manifestations of endocrine disorders: a guide for dermatologists. Am J Clin Dermatol 2003; 4: 315–331. Kriss JP. Pathogenesis and treatment of pretibial myxedema. Endocrinol Metab Clin North Am 1987; 16: 409–415. Somach SC, Helm TN, Lawlor KB, Bass J. Pretibial mucin. Histologic patterns and clinical correlation. Arch Deramatol 1993; 129: 1152–1156.

Scleredema Jabbour SA. Cutaneous manifestations of endocrine disorders: a guide for dermatologists. Am J Clin Dermatol 2003; 4: 315–331. Jackson EM, English JC III. Diffuse cutaneous mucinoses. Dermatol Clin 2002; 20: 493–501. Sibbald RG, Landolt SJ, Toth D. Skin and diabetes. Endocrinol Metab Clin North Am 1996; 25: 463–472.

Scleromyxedema Dineen AM, Dicken CH. Scleromyxedema. J Am Acad Dermatol 1995; 33: 37–43. El-Aal HA, Salem SZ, Salem A. Lichen myxedematosus: histochemical study. Dermatologica 1981; 162: 273–276.

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137

Howsden SM, Herndon JH Jr., Freeman RG. Lichen myxedematosus: a dermal infiltrative disorder responsive to cyclophosphamide therapy. Arch Dermatol 1975; 111: 1325–1330.

Nephrogenic Systemic Fibrosis Cowper SE, Su PD, Bhawan J, Robin HS, LeBoit PE. Nephrogenic fibrosing dermopathy. Am J Dermatopathol 2001; 383–393. High WA, Ayers RA, Chandler J, Zito G, Cowper SE. Gadolinium is detectable within the tissue of patients with Nephrogenic systemic fibrosis. J Am Acad Dermatol 2007; 56: 21–26. Introcaso CE, Hivnor C, Cowper S, Werth VP. Nephrogenic fibrosing dermopathy/Nephrogenic systemic fibrosis: a case series of nine patients and review of the literature. Int J Dermatol 2007; 46: 447–452.

Small Plaque Parapsoriasis Benmaman O, Sanchez JL. Comparative clinicopathological study on pityriasis lichenoides chronica and small plaque parapsoriasis. Am J Dermatopathol 1988; 10: 189–196. Lambert WC, Everett MA. The nosology of parapsoriasis. J Am Acad Dermatol 1981; 5: 373–395.

Urticaria Kossard S, Hamann I, Wilkinson B. Defining urticarial dermatitis: a subset of dermal hypersensitivity reaction pattern. Arch Dermatol 2006; 142: 29–34. Longley J, Duffy TP, Kohn S. The mast cell and mast cell disease. J Am Acad Dermatol 1995; 32: 545–561.

Urticaria Pigmentosa DiBacco RS, DeLeo VA. Mastocytosis and the mast cell. J Am Acad Dermatol 1982; 7: 709–722. Soter NA. The skin in mastocytosis. J Invest Dermatol 1991; 96: 32S–39S. Travis, WD, Li C-Y, Su SPD. Adult-onset urticaria pigmentosa and systemic mast cell disease. Am J Clin Pathol 1985; 84: 710–714.

Index

A Acantholysis, pemphigus foliaceus/erythematosusrelated, 101, 102 Acanthosis acral, 31 ichthyosis-related, 96 of nipple skin, 33, 34 Acid fast stain, 63, 67 Acral skin, normal histology of, 30–31 Acrosyringium, 14, 15 Acrotrichium, of hair follicles, 9 Actin, 79 Adenosine triphosphatase (ATPase), 6 Adipocytes, 29, 30 Adnexal tumors biopsy of, 37, 43–46 microcystic, 37, 43–46 AE1-AE3 cytokeratin marker, 76, 87 Alcian Blue/colloidal iron stain, 63, 64–65, 117, 119 Alopecia biopsy-based evaluation of, 59–60 hair follicle assessment in, 8 Amyloid, histochemical stain for, 63 Amyloidosis, 114

differential diagnosis of, 93, 115–116 lichen, 71, 115, 116 macular, 115 secondary, 115 Androgen receptor (AR), 84 Anetoderma biopsy of, 60 differential diagnosis of, 93, 106, 113–114 histochemical stain for, 63 Angiosarcoma, differential diagnosis of, 88, 89 Antibody panel (“tool box”), 75–84 epithelial markers, 75–78 hematopoietic markers, 49, 75, 81–84 mesenchymal markers, 75, 78–79 sample panels, 88–91 Anti-herpes antibodies, 84 Anti-keratin antibodies, 115 Anti-spirochete antigens, 84, 85 Apocrine glands innervation of, 24 normal histology of, 16–17 Arrector pili muscles, 26 B Bacteria tissue gram stain for, 63

139

140 Bacteria (cont.) See also names of specific bacteria Basal cell carcinoma biopsy of, 41, 42, 43 differential diagnosis of, 89 morpheic, 43 squamatized, 41, 43 Basement membrane collagen of, 23 histochemical stain for, 64 normal histology of, 17–19 Bcl-2, 83, 90 Bcl-6, 83, 90 Biopsy, 37–61 of alopecia, 59–60 of basal cell carcinoma, 41, 42, 43 of connective tissue diseases, 56–57 of dermal tumors, 46–48 of adnexal origin, 37, 43–46 determination of differential diagnosis in, 38–39 of inflammatory conditions, 50–60 of keratinocytic/presumed keratinocytic neoplasms, 41–43 margins in, 39, 40, 46 of presumed hematopoietic processes, 49 of presumed melanoma, 38–39 of presumed neoplastic processes, 37, 38–49 systematic review of, 93–94 Birbeck granules, 6 Blastomycosis, histochemical stain for, 64 Blistering diseases, biopsy-based evaluation of, 50–52 Blisters, pemphigus foliaceus/erythematosusrelated, 101, 102

Index Blood vessels ectatic, in acral skin, 31 passage through subcutaneous fat, 29 See also Vasculature Brown and Brenn (tissue gram) stain, 63, 66 Bullous lupus erythematosus, blisters associated with, 19 Bullous pemphigoid antigens, 18 Buschke-Ollendorf syndrome, 106

C Caf´e-au-lait macules, 93, 102, 104–105 Carcinoembryonic antigen (CEA), 78 Cartilage, collagen component of, 22, 23 CD1a, 6, 7, 82, 89 CD3, 82, 89, 90 CD4, 82, 89 CD5, 82 CD7, 82 CD8, 82 CD10, 82, 90 CD20, 82, 83 CD30, 82, 83 CD31, 89 CD34, 82 CD43, 82 CD68, 82, 88, 89, 90 CD79a, 82, 90 CD99, 82 CD117, 67, 82, 84 CD138, 83, 91 CD4+ T cells, 28 CD8+ T cells, 28 Ceruminous glands, 16 Chloroacetate esterase stain, 63, 71–72 Chondroitin sulfate, histochemical stain for, 65

Index Collagen, 22–23 acral, 30, 31 eosinophilic, 22 of eyelid skin, 32 of fibroblast origin, 29 histochemical stains for, 69, 70 of nails, 32 in scleroderma, 119, 120 type I, 22, 29 type II, 22, 23, 29 type III, 22 type IV, 22 type V, 22 type VI, 22 type VII, 19, 22 Collagenoma, 66, 69, 108 Colloidal iron stain, 63, 65–66, 119, 120 Congo red stain, 63, 70 Connective tissue diseases biopsy-based evaluation of, 56–57 differential diagnosis of, 105, 106 Connective tissue nevus, 60, 93, 106–108 Connective tissue stains, 69–70 Corneocytes, paraketotic, 99 Corynebacterium minutissimum, 98 Coup de sabre, 110 Crystal violet stain, 71 Cutis laxa differential diagnosis of, 106, 108–109 histochemical stain for, 66 Cyst, pilar, 45–46 Cytokeratin(s), as diagnostic markers, 75–78 See also specific cytokeratins Cytokeratin 20, 8

D Dendrocytes dermal, 19, 27–28, 29

141 immunohistochemical markers for, 80 Deposition diseases, dermal, 102, 114–120 Dermal duct, 14 Dermal tumors, biopsy of, 44–46 of adnexal etiology, 37, 43–46 Dermatitis herpetiformis, 19, 51, 108, 109 seborrheic, 53 spongiotic, 89 stasis, 73 “Dermatitis”, biopsy-based evaluation of, 52–53 Dermatofibroma, 27 biopsy of, 46–48 differential diagnosis of, 46–48, 90 mesenchymal markers for, 78, 79 Dermatofibrosarcoma protuberans, 46, 48, 90 Dermatomyositis, mucin detection in, 65 Dermatosis, digitate, 124–125 Dermis of eyelid skin, 32 normal histology of, 19–29 papillary, 20, 21, 22, 28 reticular, 20, 21, 22, 26, 28 thickness of, 1, 30 in eyelid, 32 in scleroderma, 119 Desmin, 79 Diabetes mellitus, scleroderma associated with, 119 Differential diagnosis, of normal skin, 38–39, 93–128 amyloidosis, 93, 115 anetoderma, 93, 113–114 caf´e-au-lait macule, 93, 104–105 conditions with minimal inflammation, 124 connective tissue nevus, 93, 106–108 cutis laxa, 108–109

142 Differential diagnosis, of normal skin (cont.) dermal deposition disorders, 114 differential diagnosis of, 87, 88, 89 erythrasma, 93, 94, 98–100 ichthyoses, 93, 96 lamellar, 94, 97–98 vulgaris, 100 X-linked, 94, 95, 96–97 mid-dermal elastolysis-related wrinkling, 93, 106, 114 morphea, 106, 110–112 nephrogenic systemic fibrosis, 93, 122–123 nevus depigmentosus (nevus achromicus), 102, 105–106 pagetoid tumors, 88 parapsoriasis, 93, 124–125 pemphigus foliaceus/erythematosus, 93, 100, 101–102 pretibial myxedema, 93, 117–118 scleroderma, 93, 110–112, 119 scleromyxedema, 93, 121–122 spindle cell tumors, 88 squamous cell carcinoma, 41, 43, 87, 88 tinea versicolor, 93, 94–96 urticaria, 93, 126 urticaria pigmentosa, 93, 126–128 vitiligo, 91, 93, 102–103 Donovan bodies, 68 E Eccrine ducts normal histology of, 14, 15 in scleroderma, 119 Eccrine glands acral, 30 innervation of, 24 normal histology of, 13, 15, 16

Index Elastic tissue fibers, 23–24 in anetoderma, 113, 114 in connective tissue nevus, 107, 108 in cutis laxa, 108, 109 histochemical stains for, 65, 108 in mid-dermal elastolysis, 114 Elastic von Gieson stain, 65, 65–66 Elastolysis focal dermal, see Anetoderma generalized (cutis laxa), 65, 108, 110 histochemical stain for, 65–66 mid-dermal, as wrinkling cause, 93, 108, 114 Elaunin, 23 Epidermis acral, 30, 31 appendages of, 8–17 of eyelid skin, 32 thickness of, 1, 30 in eyelid, 32 Epidermolysis bullosa acquisita (acquired) blisters associated with, 19 immune deposit localization in, 52 blisters associated with, 18, 19 dystrophic, 19 junctional type of, 19 simplex, 18, 19 Epithelia, glandular, of nipple skin, 33, 34 Epithelial markers, 75–78 Epithelial membrane antigen (EMA), 78, 88 Erythema nodosum, biopsy of, 59 Erythematosus, differential diagnosis of, 93, 101–102 Erythrasma, differential diagnosis of, 93, 94, 98–100 Estrogen receptor (ER), 84 Eumelanin, 5 Eyelids, normal cutaneous histology of, 32

Index F Factor XIIIa, 27, 79, 80 Fasciitis, eosinophilic, 110 Fat, subcutaneous normal histology of, 29–30 thickness of, 1, 30 Fibroblasts, dermal, 19, 29 in nephrogenic systemic fibrosis, 122, 123 in pretibial myxedema, 117, 118 in scleromyxedema, 121 Fibrohistiocytic-differentiated tumors, 29 Fibronectin, in lamina lucida, 19 Fibrosis, nephrogenic systemic biopsy of, 59 differential diagnosis of, 93, 122–123 Fibroxanthoma, atypical, 78 Fite stain, 63, 67, 68 Fontana stain, for melanin, 63, 71–72, 102, 103, 105 Fordyce spots, 12, 34 Fungi histochemical stain for, 64 See also names of specific fungi

G Giemsa stain, 63, 67–68 Glomus cells, 26, 27 Glycogen, histochemical stain for, 64 Goblet cells, 32 Granuloma annulare, mucin detection in, 65 Granuloma annular elastolytic, 65 Granuloma inguinale, Donovan body detection in, 68

H Haarscheibe, 8 Hair follicles anatomic connections with

143 apocrine glands, 16 sebaceous glands, 9, 12, 13 as arrector pili insertion site, 26 keratins of, 75 normal histology of, 8–12 anagen phase, 8, 9–10 catagen phase, 8, 11 telogen phase, 8, 11–12 Hamartoma, 106 Hematopoietic infiltrates/tumors biopsy of, 49 histochemical stain for, 71, 72 immunohistochemical markers for, 49, 75, 81–84 Hemidesmosomes, 18 Hemochromatosis, 73 Heparan sulfate, histochemical stain for, 65 Herpes simplex virus infection, biopsy-based evaluation of, 53–54 Histiocytes, 29 Histiocytoma, epitheloid, 90 HLA-DR, 6 HMB-45, 80, 81, 82, 91 Human papilloma virus infection, biopsy-based evaluation of, 53–54 Hyaluronic acid, histochemical stain for, 65 Hypergranulosis, acral, 31 Hyperkeratosis acral, 31 ichthyosis-related, 96, 97 Hyperpigmentation caf´e-au-lait macule-related, 104 melanosomes and melanocytes in, 5–6 of nipple skin, 33 Hyperplasia cutaneous lymphoid, 90 pseudoepithelioomatous, 55 Hypersensitivity reaction, dermal, 53 Hyphae, 95, 96

144 I Ichthyosis, 93, 96 acquired variant, 97, 100 lamellar, 94, 97–98 vulgaris, 100 profilaggrin defects in, 3 X-linked, 94, 96–97 Immunofluorescence studies, of blisters, 51–52 Immunoglobulin deposits, in lupus, 57 Immunopathology, in diagnostic dermatopathology, 75–91 antibody panel (“tool box”) in, 75–84 epithelial markers, 75–78 hematopoietic markers, 49, 75, 81–84 mesenchymal markers, 75, 78–79 neuroectodermal markers, 75, 79–81 sample panels, 88–91 interpretation of findings in pitfalls in, 86–87 requirements for, 85 miscellaneous markers in, 84–85 strategy for, 87–91 Infectious diseases biopsy-based evaluation of, 53–55 See also specific infectious diseases Inflammation/inflammatory conditions biopsy of, 50–60 cutis laxa-related, 108 dermal vasculature in, 20 mast cells in, 28 minimal, conditions associated with, 124–128 morphea-related, 110, 111 Infundibulum, of hair follicles, 9 Involucrin, 3 Iron, histochemical stains for

Index colloidal iron, 63, 65, 119, 120 Perl’s stain, 63, 72

K Kappa (immunohistochemical stain), 83 Keratin(s), of Merkel cell origin, 8 Keratin 5, 18 Keratin 14, 18 Keratinocytes basal, 17, 18 melanin in, 104 melanosome complexes in, 6 mucosal, 34, 35 normal histology of, 1–5 of the stratum basalis, 4, 5 of the stratum corneum, 2, 3 of the stratum granulosum, 4 Keratinocytic neoplasms, biopsy of, 41–43 Keratolinin, 3 Keratoses, misdiagnosed as squamous cell carcinoma, 41 Ki-67, 83, 84, 86

L Lambda (immunohistochemical stain), 83 Lamina densa, 17, 18, 19 Lamina lucida, 17, 18–19 immune deposit localization in, 52 Laminin in lamina densa, 19 in lamina lucida, 19 Langerhans cells, normal histology of, 6–7 Leiomyoma, differential diagnosis of, 69, 88, 89 Leishmaniasis, mast cell detection in, 68 Leprosy, as anetoderma cause, 113 Leukocyte common antigen, 83

Index Lichen simplex chronicus, 115 Lupus discoid, 57 erythematosus, 64 as anetoderma cause, 113 mucin detection in, 65 profundus, 57 subacute, 57 Lupus band test, 57 Lymphocytes dermal, 19 peri-eccrine, 112, 114 in urticaria pigmentosa, 126 Lymphoma B cell, 90 cutaneous marginal zone, 49 large cell, 83 anaplastic, 90

M Macular atrophy, see Anetoderma Macules caf´e-au-lait, 93, 102, 104–105 hypopigmented, 105 MART-1, 79, 80, 81, 88, 91, 102 Masson’s trichome stain, 63, 69–70 Mast cells, 28, 29 histochemical stains for, 67, 69, 72 immunohistochemical markers for, 82, 84, 91 in urticaria pigmentosa, 126, 127 Mastocytoma, 84 Mastocytosis, mast cell detection in, 67 Meibomian glands, 12 Meissner’s corpuscles, 24, 25 acral, 30 Melanin in caf´e-au-lait macules, 104, 105 giant granular, 104, 105 histochemical stain for, 63, 71–72, 102, 104, 105 Melanocytes

145 acral, 30 of caf´e-au-lait macules, 104 of nails, 32 of nipple skin, 33 normal histology of, 5–6 in vitiligo, 102, 103 Melanocytic lesions, benign, 84 Melanoma biopsy of, 38–39 Clark’s levels of, 20 differential diagnosis of, 88, 89 immunohistochemical markers for, 82, 84 Melanosomes, transfer to lysosomes, 5 Merkel cell carcinoma, differential diagnosis of, 89 Merkel cells immunohistochemical markers for, 76, 78 normal histology of, 8 Mesenchymal markers, 75, 78–79 MiB1, 83, 84 Microgranulomata, 6 Micro-ophthalmia transcription factor, 80 Mohs’ surgery, 39 Moll’s glands, 16 Montgomery tubercles, 12 Morphea, 106, 110–112 Mucin, histochemical stain for, 65, 66 Mucinosis focal dermal, 65, 66 follicular, 65 in nephrogenic systemic fibrosis, 122 papular (scleromyxedema), 121–122 in pretibial myxedema, 117, 118 Mucocutaneous end organs, 24 Mucopolysaccharides acid, 64, 118 histochemical stains for, 64, 65 neutral, 64

146 Mucopolysaccharides (cont.) non sulfated, 65 sulfated, 65 Mucosa/mucous membranes differentiated from skin, 34–35 ectopic glands of, 12 normal cutaneous histology of, 34–35 Muscles, dermal, 19, 26–27 of nipple skin, 33, 34 Mycobacteria, 67 histochemical stains for, 67

N Nails keratins of, 73 normal cutaneous histology of, 32–33 Nephrogenic systemic fibrosis, 122–123 biopsy of, 59 differential diagnosis of, 93, 122–123 Nerves, dermal, 19, 24–25 passage through subcutaneous fat, 29 Neural tumors, distinguished from leiomyoma, 69 Neuroectodermal markers, 75, 79–81 Neuroendocrine carcinoma, metastatic, differential diagnosis of, 89 Neurofibromatosis, caf´e-au-lait macules associated with, 104 Neutrophils, of the stratum corneum, 94 Nevus connective tissue, 60, 93, 106–108 depigmentosus (nevus achromicus), 102, 105–106 epidermal, 60

Index epitheloid spitz, 90 Nipple, normal cutaneous histology of, 33–34

O Odland bodies, 2 Orthokeratosis, 2, 3, 100 acral, 31 ichthyosis-related, 97, 100 of nipple skin, 33 Orthokeratotic plates, of nails, 32 Ostium, of hair follicles, 9 Oxytalin, 23

P Pacini-Vater (Pacinian) corpuscles, 24, 25 Pagetoid cell tumors, differential diagnosis of, 88 Paget’s disease differential diagnosis of, 88 extramammary, 65 immunohistochemical markers for, 76, 78 Pan-cytokeratin markers, 76 Panniculitis, biopsy of, 58–59 Papillomatosis, of nipple skin, 33, 34 Papulosis, lymphomatoid, 90 Parakeratosis, 124, 125 mucosal, 34 Parapsoriasis differential diagnosis of, 93, 124–125 small plaque, 124–125 Pemphigus foliaceus/erythematosus as blister cause, 101, 102 differential diagnosis of, 93, 100, 101–102 Penicillamine therapy, as anetoderma cause, 113 Pericytes, dermal, 29 Periodic acid-Schiff (PAS) stain, 63, 64, 94, 95–96

Index Perls’ iron stain, 63, 72 p53 (epithelial transcription marker), 78 Pilar cyst, 46 Pityriasis lichenoides et varioliformis, 90 Pityrosporum versicolor, 94 Plasma cells in morphea/scleroderma, 110, 112 mucosal, 34 Polymerase chain reaction (PCR) studies, 49, 55 Pretibial myxedema differential diagnosis of, 93, 117–118 mucin detection in, 65 Primitive neuroectodermal tumors, differential diagnosis of, 89 Profilaggrin, 3 Progesterone receptor (PR), 84 Proliferation markers, 84 Prostate specific antigen (PSA), 84 Prostatic alkaline phosphatase (PAP), 84 Prussian Blue reaction, 73 p63 (epithelial transcription marker), 78 Purpura, Henoch-Schonlein, 57 R “Rash”, biopsy-based evaluation of, 52–53 Renal disease, nephrogenic systemic fibrosis associated with, 122 Reticulohistiocytoma, 90 S Salivary glands and ducts, 34 Salt split-skin technique, 52 Scleroderma differential diagnosis of, 93, 106, 110–112, 119–120

147 mucin detection in, 65 Scleromyxedema differential diagnosis of, 93, 121–122 mucin detection in, 65 Sebaceous glands of eyelid skin, 32 of nipple skin, 33, 34 normal histology of, 12–13 Shagreen patches, 107 Sialomucin, histochemical stain for, 65 Sirius red stain, 71 Skin differentiated from mucosa, 34–35 normal histology of, 1–35 dermis, 19–29 epidermis, 1–17 “special sites”, 30–35 subcutaneous fat, 29–30 Skin color, role of melanosomes in, 5–6 Small blue cell tumors, differential diagnosis of, 89 Solar elastosis, elastic tissue in, 23 Solar lentigo, differentiated from primary melanocytic neoplasm, 81 S100, 6, 79, 82, 88, 89, 90, 102 Spindle cell neoplasms, differential diagnosis of, 88 Spindle cells, dermal, 29 Spiradenocarcinoma, 45–46 Spirochetes antibodies to, 84, 85 histochemical stains for, 67, 70 Spongiosis parapsoriasis-related, 124, 125 tinea versicolor-related, 94 Squamous cell carcinoma biopsy of, 41 differential diagnosis of, 40, 42, 88, 89

148 Squamous cell carcinoma (cont.) immunohistochemical markers for, 76, 78, 87 misdiagnosis of, 41, 42, 87 sarcomatoid, 76, 78 spindle cell, 76, 78, 88 Stains histochemical, 63–73 acid fast, 63, 67 Alcian Blue/colloidal iron, 63, 64–65, 117, 119 Brown and Brenn (tissue gram), 63, 66 chloroacetate esterase, 63, 71–72 Congo red, 63, 71 elastic von Gieson, 63, 65–66 Fite, 63, 67, 68 Fontana stain for melanin, 63, 71–72, 102, 103, 105 Giemsa, 63, 67–68 Masson’s trichrome, 63, 69–70 periodic acid-Schiff (PAS), 63, 64, 94, 95–96 Perl’s iron, 63, 73 Warthin-Starry, 63, 68–69, 70 immunohistochemical, 75–84 epithelial markers, 75–78 hematopoietic markers, 49, 75, 81–84 mesenchymal markers, 75, 78–79 neuroectodermal markers, 75, 79–81 Stratum basalis normal histology of, 1, 4–5 in pemphigus foliaceus/erythematosus, 101 Stratum corneum acral, 30 of eyelid skin, 32 in ichthyosis, 94, 96 neutrophils of, 94 normal histology of, 1, 2–3

Index orthokeratosis of, 2, 3 subtle alterations in, 94 Stratum granulosum in erythrasma, 101 normal histology of, 1, 3 in pemphigus foliaceus/erythematosus, 101, 102 Stratum lucidum, acral, 30 Stratum spinosum Langerhans cells of, 7 normal histology of, 1, 3–4 Sublamina densa, 17, 18, 19 Sun exposure, effect on dermal elastic tissue fibers, 24 Suquet-Hoyer canal, 26 Syphilis, as anetoderma cause, 113 Syringoma, 42, 43 Systemic lupus erythematosus, 57 Systemic lupus erythematosus, See Lupus, erythematosus T Telangiectasia macularis eruptiva perstans, 126 Thioflavin T stain, 71 Thyroid transcription factor-1 (TTP-1), 84 Thyrotoxicosis, 117 Tinea, biopsy-based evaluation of, 53–56 Tinea versicolor, 93, 94–96 Transglutaminase, 3 Trichoepithelioma, biopsy and differential diagnosis of, 41, 42–43, 44–45 Tricholimmalcarcinoma, 44 Tuberous sclerosis, Shagreen patches in, 107 Tyrosinase, 80 U Urticaria cutis laxa-related, 108 differential diagnosis of, 93, 126

Index mast cell detection in, 67 Urticaria pigmentosa differential diagnosis of, 93, 126–128 mast cell detection in, 67

V Vasculare plexus, 12, 20 Vasculature, dermal, 19, 20–21 glomus cells surrounding, 26, 27 Vasculitis, biopsy of, 57–58 Vellus hairs, 32 Verhoff van Gieson stain, 108

149 Vimentin, 79 Vitiligo differential diagnosis of, 91, 93, 102–103 melanin loss in, 72

W Warthin-Starry stain, 63, 68, 70

Y Yeast, 95, 96