Differential diagnosis is at its most accurate and efficient when clinical presentation and histopathological features are considered in correlation with one another. With this being so, the expert team behind this atlas has integrated both perspectives to create an innovative and essential resource for all those involved with the diagnosis of tumors, cysts, and nevi. Almost 1,400 full-color images clearly illustrate common patterns and variants of tumorous lesions of the skin and are helpfully contextualized by concise, straightforward descriptions of key features and diagnostic clues.
Whether they are aspiring or experienced practitioners, dermatologists and pathologists of all levels will find this an insightful and practically applicable addition to their bookshelf. Its far-reaching and easy-to-navigate coverage of relevant diseases of the skin provides trainees with an excellent grounding in the area, while practicing specialists may benefit from its use as a tool for the differential diagnoses of borderline cases.
Atlas of Dermatopathology: Tumors, Nevi, and Cysts offers a uniquely balanced, clear, and comprehensive guide to what can be a difficult process, and will be of tremendous assistance tostudents, dermatologists, dermatopathologists, and pathologists everywhere.
Table of Contents
Preface xv
Acknowledgments xvii
1 EPIDERMIS 1
Nevi 2
Epidermal Nevus 2
Variant: Inflammatory Linear Verrucous Epidermal Nevus (ILVEN) 3
Keratoses 4
Seborrheic Keratosis (SK) and Variants 4
Variant: Acanthotic Seborrheic Keratosis 4
Variant: Reticulated, Pigmented Seborrheic Keratosis 6
Variant: Flat Seborrheic Keratosis 6
Variant: Papillomatous Seborrheic Keratosis 7
Variant: Activated (Irritated) Seborrheic Keratosis 7
Variant: Dermatosis Papulosa Nigra 7
Variant: Melanoacanthoma (Pigmented Seborrheic Keratosis) 8
Variant: Clonal (Intraepidermal) Seborrheic Keratosis (Borst- Jadassohn) 9
Variant: Seborrheic Keratosis with Monster Cells (Bowenoid) 10
Variant: Hyperkeratotic Seborrheic Keratosis (Stucco Keratosis) 11
Confluent and Reticulate Papillomatosis (Gougerot and Carteaud) 12
Reticulate Pigmented Anomaly of the Flexures (Dowling-Degos Disease) 13
Acanthosis Nigricans 14
Solar (Actinic) Keratosis 15
Variant: Acantholytic Solar Keratosis 16
Variant: Atrophic Solar Keratosis 16
Variant: Lichen Planus‐Like Solar Keratosis 17
Variant: Hypertrophic (Bowenoid) Solar Keratosis 18
Cornu Cutaneum 18
Acanthomas, Non‐Viral 19
Solar Lentigo 19
Callus, Factitial Acanthoma 20
Knuckle Pads (Chewing Pads) 21
Pale (Clear) Cell Acanthoma 22
Large Cell Acanthoma 23
Differential Diagnosis: Epidermolytic Acanthoma 24
Differential Diagnosis: Congenital Ichthyosiform Erythroderma 25
Acantholytic Acanthoma 26
Warty Dyskeratoma 27
Porokeratoma (Porokeratosis Mibelli) 30
Acanthomas, Viral 31
Verruca Vulgaris 31
Variant: Verruca Plana 33
Variant: Condyloma Acuminatum 34
Bowenoid Papulosis 35
Acrokeratosis Verruciformis (Hopf) 37
Molluscum Contagiosum 38
“Pseudocarcinomas” and Neoplasms with Intermediate Malignant Potential 40
Keratoacanthoma (KA) 40
Epithelioma Cuniculatum (Verrucous Carcinoma) (EC/VC) 44
Papillomatosis Cutis Carcinoides 45
Florid Papillomatosis of the Oral Cavity (Oral Verrucous Carcinoma) 46
Buschke-Löwenstein Tumor (Giant Condyloma) 47
Malignant Epidermal Neoplasms 48
Bowen’s Disease (Carcinoma in situ) 48
Variant: Clear Cell Bowen’s Disease 50
Variant: Cutaneous Horn (Cornu Cutaneum) on Bowen’s Disease 51
Variant: Pigmented (Anogenital) and Clonal Bowen’s Disease 52
Variant: Erythroplasia of Queyrat and Vulvar Intraepithelial Neoplasia 53
Basal Cell Carcinoma (BCC) 54
Variant: Nodular BCC 54
Variant: Infundibulocystic BCC 56
Variants of BCC With Ductal, Matrical or Sebaceous Differentiation 57
Variant: Superficial BCC 60
Variant: Pigmented BCC 61
Variant: Adenoid‐Cystic BCC 62
Variant: Sclerodermiform (Morpheaform) BCC 64
Clinical Variants: Ulcerating BCCs 66
Histological Variants: Metatypic BCC with Squamoid Differentiation 67
Syndromatic BCC (Basal Cell Nevus Syndrome, Gorlin-Goltz) 69
Fibroepithelioma of Pinkus 70
Squamous Cell Carcinoma (SCC) 72
Variant: Well‐Differentiated SCC 72
Variant: Acantholytic SCC (Epithelioma Spinocellulare Segregans of Delacretaz) 74
Variant: Myxoid SCC 76
Variant: Follicular (Infundibular) SCC 77
Variant: Spindle Cell (Fusicellular) SCC 78
Squamous Cell Carcinomas in Special Sites 79
2 ADNEXAL 85
Sweat Gland Differentiation 86
Nevi, Hyperplasias, and Benign Adnexal Neoplasms (BAN) 86
Eccrine Differentiation 86
Apocrine Differentiation 93
Malignant Adnexal Neoplasms 105
Eccrine Differentiation 105
Apocrine Differentiation 109
Sebaceous Differentiation 110
Hyperplasias and Hamartomas 111
Ectopic (Heterotopic) Sebaceous Glands (Fordyce Glands) 111
(Senile) Sebaceous Gland Hyperplasia 112
Nevus Sebaceous (Jadassohn) 113
Variant: Pilo‐Sebaceous Hamartoma 114
Benign Neoplasms 114
Sebaceous Adenoma 114
Muir-Torre Syndrome 115
Sebaceous Epithelioma (Sebaceoma) 116
Malignant Neoplasms 118
Sebaceous Carcinoma 118
Hair Follicle Differentiation 119
Nevi, Hyperplasia, and Hamartomas 119
Hair Follicle Nevus 119
Conical Infundibular Acanthoma (Giant Dilated Pore of Winer) 120
Benign Neoplasms 121
Pilar Sheath Acanthoma 121
Trichilemmoma (Tricholemmoma) 122
Tumor of the Follicular Infundibulum (Infundibuloma) 124
Trichoepithelioma (Superficial Trichoblastoma) 125
Trichoblastoma (Trichoblastic Fibroma; Immature Trichoepithelioma) 127
Trichoepithelioma (Sclerosing Epithelial Hamartoma) 131
Trichofolliculoma (Folliculosebaceous Cystic Hamartoma) 133
Trichoadenoma (Nikolowski) 136
Pilomatricoma (Calcifying Epithelioma Malherbe) 137
Proliferating Trichilemmal (Pilar) Tumor (PTT) (Proliferating Trichilemmal Cyst) 138
Malignant Neoplasms 140
Malignant Pilomatricoma (Pilomatrical Carcinoma) 140
Trichilemmal Carcinoma 141
Trichoblastic Carcinoma 142
Pilosebaceous Mesenchyme 143
Benign Neoplasm 143
Trichodiscoma (Follicular Fibroma, Fibrofolliculoma, Perifollicular Fibroma) 143
3 PAGET’S DISEASE 145
Mammary Paget’s Disease 146
Extramammary Paget’s Disease 146
4 MELANOCYTES 149
Non‐Neoplastic Hyperpigmentations 150
Ephelides (Genuine Freckles) 150
PUVA (Psoralen UVA) Lentigo 150
“Nevus” Spilus (Speckled Lentiginous Nevus; Café‐Au‐Lait Spot) 151
“Ink” Spot Lentigo (Reticulated Melanocytic Macule) 152
Senile Freckles (Solar [Actinic] Lentigo) 153
Mucosal Lentiginous Spots (Lip, Buccal, and Genital Mucosa) 154
Nevi 155
Common Acquired Melanocytic Nevi 155
Melanosis Neviformis (Pigmented Hairy Epidermal Nevus; Becker Nevus) 155
Junctional Nevus 156
Compound Nevus 157
Dermal Nevus 158
Variant: Miescher’s Nevus (Dermal Nevus) 160
Variant: Balloon Cell Nevus 161
Variant: “Activated” Acral (Lentiginous) Melanocytic Nevus 161
Variant: (Atypical) Genital Melanocytic Nevus 162
Variant: Halo Nevus (Leukoderma Centrifugum Acquisitum; Sutton Nevus) 163
Variant: Eczematoid Melanocytic (Meyerson’s) Nevus 165
Variant: Osteo‐Nevus of Nanta 166
Variant: Combined Epithelioid Spitzoid Nevus, “Wiesner Nevus” (BAP-1 Deficient Epithelioid Melanocytic Tumor) 167
Variant: Recurrent (Persistent) Melanocytic Nevus (Pseudomelanoma) 167
Variant: Nevus in Pregnancy 168
Variant: Ancient Nevus 170
Blue Nevi 171
Common Blue Nevus 171
Common Blue Nevus 172
Dermal Melanocytosis 177
Nevus Fuscoceruleus (Ota; Ito; Mongolian Spot) 177
Spindle and/or Epithelioid Cell Nevus 178
Common Nevus of Spitz 178
Variants of Spindle and Epithelioid Cell Nevus 179
Variant: Pigmented Spindle Cell Nevus (Reed) 182
Benign Melanocytic Lesions with Peculiar Structural Features 183
Melanocytic Nevus with Clonal Proliferation 183
Atypical (Dysplastic) Melanocytic (Clark’s) Nevus (B‐K Mole Syndrome) 185
Congenital Nevi, Small and Medium‐Sized (1.5-20 cm) 186
Malignant Melanocytic Neoplasms 188
Lentigo Maligna Dubreuilh (Hutchinson’s Freckle) 188
Malignant Melanoma 189
Variant: Superficial Spreading Melanoma (SSM) 190
Variant: Lentigo Maligna Melanoma (LMM) 192
Variant: Nodular Melanoma (NM) 193
Variant: Acral Lentiginous Melanoma (ALM) 194
Variant: Melanoma in Large Congenital Melanocytic Nevus (LCMN) 196
Variant: Cutaneous Metastasis of Melanoma 197
Special Localisations of Malignant Melanoma 204
Tumor Thickness and Levels 205
Common Clinical Differential Diagnoses of Malignant Melanoma 205
5 CONNECTIVE TISSUE 207
Nevi 208
Connective Tissue Nevus (Shagreen Patch; Cobblestone Nevus; Nevus Collagenicus) 208
Fibrous Neoplasms 209
Soft Fibroma (Skin Tag; Acrochordon) 209
Perifollicular Fibroma (Fibrofolliculoma; Trichodiscoma) 210
Variant: Sclerotic Fibroma (Plywood Fibroma; Storiform Collagenoma) 211
Variant: Fibrous Papule of the Nose 212
Variant: Pleomorphic Sclerosing Fibroma with Multinucleated Cells 212
Keloid 213
Infantile Digital Fibromatosis (Inclusion Body Fibromatosis; Recurring Digital Fibrous Tumor of Children; Reye’s Tumor) 214
Malformations with Supernumerary Tissue Elements 216
Supernumerary Digit (Rudimentary Digit; Rudimentary Polydactyly) 216
Differential Diagnosis: Acral Acquired Fibrokeratoma 216
Accessory Tragus (Preauricular Tag) 217
Accessory Nipple (Ectopic Breast; Polythelia) 218
Fibrohistiocytic Neoplasms 218
Dermatofibroma (Benign Fibrous Histiocytoma; Fibroma Durum; Sclerosing Hemangioma) 218
Dermatofibrosarcoma Protuberans 227
Variant: Pigmented Dermatofibrosarcoma Protuberans (Bednar’s Tumor) 230
Variant: Giant Cell Fibroblastoma 231
Pleomorphic Dermal Sarcoma (PDS) 231
Miscellaneous Tumors 234
Epithelioid Sarcoma 234
Dermatomyofibroma 236
6 VESSELS 239
Hamartomas, Nevi, and Malformations 240
Phacomatosis Pigmentovascularis 240
Eccrine Angiomatous Hamartoma 241
Nevus Anemicus 242
Capillary Malformations 242
Nevus Flammeus (Port-Wine Stain) 242
Nevus Araneus (Spider Angioma) 244
Cutis Marmorata Telangiectatica (van Lohuizen) (Nevus Vascularis Reticularis) 245
Congenital Telangiectatic Erythema (Bloom’s Syndrome) 247
Venous Malformations 248
Blue Rubber Bleb Nevus Syndrome (Familial Venous Malformation) 248
Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu) 249
Angioma Serpiginosum 250
Venular Aneurysm (Venous Lake) 251
Cavernous Hemangioma (in Maffucci Syndrome) 252
Sinusoidal Hemangioma 253
Spindle Cell Hemangioma (Formerly Spindle Cell Hemangioendothelioma) 254
Arteriovenous Malformations 256
Acral Arteriovenous Hemangioma (Cirsoid Aneurysm) 256
Glomuvenular Malformation (“Glomangioma”) 257
Lymphatic Malformations 259
Superficial Lymphatic Malformation (Superficial Lymphangioma) 259
Cystic Lymphatic Malformation (Cystic Hygroma) 260
Targetoid Hemosiderotic (Hobnail) Hemangioma 261
Progressive Lymphangioma (Benign Lymphangioendothelioma) 262
Lymphangiomatosis 263
Angiokeratomas 264
Verrucous Hemangioma (Venous Malformation) 265
Variant: Solitary Angiokeratoma 268
Variant: Angiokeratoma Circumscriptum Naeviformis 269
Variant: Fordyce Angiokeratoma 269
Variant: Angiokeratoma Acroasphycticum Digitorum (Mibelli) 269
Variant: Multiple “Pinpoint” Angiokeratomas (Angiokeratoma Corporis Diffusum; Fabry’s Disease) 269
Variant: Acral Pseudolymphomatous Angiokeratoma of Children (APACHE) 269
Hyperplasias 270
Granuloma Pyogenicum (Lobular Capillary Hemangioma; Botryomykoma) 270
Differential Diagnosis: Pyogenic Granuloma‐Like Granulation Tissue 272
Bacillary Angiomatosis 273
Verruga Peruana 274
Intravascular Papillary Endothelial Hyperplasia (Masson) 275
Acroangiodermatitis Mali (Pseudo‑Kaposi’s Sarcoma) 276
Benign Vascular Neoplasms 278
Epithelioid Hemangioma (Angiolymphoid Hyperplasia with Eosinophilia, ALHE) 278
Endothelial Differentiation 280
Infantile Capillary and Congenital Hemangioma 280
Cherry Angioma (Senile Hemangioma) 281
Microvenular (Microcapillary) Hemangioma 282
Tufted Angioma 283
Kaposiform Hemangioendothelioma 285
Glomeruloid Hemangioma in POEMS Syndrome 287
Pericytic Differentiation 288 Imitator: Solitary Fibrous Tumor of the Skin (SFT) 289
Myopericytoma (Infantile Myofibromatosis; Perivascular Myoma (incl. Myofibroma)) 290
Glomoid and Myoid Differentiation 292
Glomus Tumor 292
Angioleiomyoma (Angiomyoma; Vascular Leiomyoma) 294
Recently Described Benign Vascular Tumors 296
Symplastic Hemangioma 296
Papillary Hemangioma 297
Vascular Neoplasms of Intermediate Malignant Potential 298
Kaposi’s Sarcoma (KS) 298
Retiform Hemangioendothelioma 305
Composite Hemangioendothelioma 306
Papillary Intralymphatic Angioendothelioma (PILA) (Malignant Endovascular Papillary Angioendothelioma (Dabska Tumor); Endovascular Papillary Hemangioendothelioma) 306
Radiation‐Induced Atypical Vascular Lesion (AVL) (Benign Lymphangiomatous Papule (BLAP)) 308
Vascular Neoplasms with High Malignant Potential 309
Cutaneous Angiosarcoma 309
Radiation‐Induced (Postradiation) Angiosarcoma 312
Epithelioid Hemangioendothelioma 312
Epithelioid Angiosarcoma 315
Differential Diagnosis: Acantholytic (Angiosarcoma‐Like) Squamous Cell Carcinoma 316
Glomangiosarcoma (Malignant Glomus Tumor) 317
Other Neoplasms with Significant Vascular Component 318
Multinucleate Angiohistiocytoma 318
Angiofibroma (Adenoma Sebaceum Associated with Pringle-Bourneville Disease) 319
Angiolipoma 321
Angiolipoleiomyoma (Angiomyolipoma) 322
Angiomyxoma 322
Intralymphatic Histiocytosis 324
Kimura’s Disease 325
7 FAT 327
Nevus (Hamartoma) 328
Nevus Lipomatosus Superficialis Hoffmann Zurhelle 328
Neoplasms of Fat Tissue 329
Benign Neoplasms 329
Common Lipoma and Lipomatosis 329
Angiolipoma (see Vessels, Chapter 6) 330
Angiomyolipoma (see Vessels, Chapter 6) 330
Spindle Cell Lipoma 330
Pleomorphic Lipoma (see Pleomorphic Liposarcoma) 332
Hibernoma 332
Malignant Neoplasms 333
Cutaneous Liposarcoma 333
8 MUSCLE 337
Benign Neoplasms 338
Piloleiomyoma (Pilar Leiomyoma) 338
Angioleiomyoma (see Vessels, Chapter 6) 340
Rhabdomyoma, Adult Type 340
Malignant Neoplasms 341
Rhabdomyosarcoma 341
Superficial Leiomyosarcoma 342
9 NERVES 345
Benign Neoplasms 346
Schwannoma (Neurilemmoma) 349
Solitary Neuroma (“Palisaded Encapsulated Neuroma”) 352
Variant: Traumatic Neuroma 353
Granular Cell Tumor (Abrikossoff) 354
Dermal Nerve Sheath Myxoma (Myxoid Neurothekeoma) 356
Variant: Cellular Neurothekeoma 357
Pacinian Neurofibroma (Pacinoma) 358
Malignant Neoplasms 358
Malignant Peripheral Nerve Sheath Tumor (Malignant Schwannoma) 358
Malignant Granular Cell Tumor 360
Neuroendocrine Neoplasm 360
Primary Neuroendocrine (Merkel Cell, Trabecular) Carcinoma of the Skin 360
10 MAST CELLS 363
Solitary Cutaneous Mast Cell Proliferation 364
Cutaneous Mastocytoma 364
Diffuse Cutaneous Mast Cell Proliferations 365
Urticaria Pigmentosa (Juvenile Maculopapular Mastocytosis) 365
Telangiectasia Macularis Eruptiva Perstans (Adults) 365
Systemic Mast Cell Proliferation 367
Involvement of Skin and Bone Marrow 367
11 HISTIOCYTES 369
Langerhans Cell Histiocytoses (LCH) 370
Precursors of Langerhans Cell Histiocytoses 370
Congenital Self‐healing Reticulohistiocytosis (Hashimoto-Pritzker) 370
Indeterminate Cell Histiocytosis 371
Langerhans Cell Histiocytoses (Histiocytosis X) 371
Congenital Langerhans Cell Histiocytosis (Letterer-Siwe Disease) 372
Hand-Schüller-Christian Adult LHC Histiocytosis 374
Solitary Langerhans Cell Tumor (Eosinophilic Granuloma) 375
Non‐Langerhans Cell Histiocytoses 376
Proliferative 376
Proliferative Histiocytoma (Progressive Nodular Histiocytosis, PNH) 376
Benign Cephalic Histiocytosis 377
Multicentric Reticulohistiocytosis (Lipoid Dermatoarthritis) (Solitary Reticulohistiocytoma) 378
Sinus Histiocytosis With Massive Lymphadenopathy 379
Granulomatous Storing 380
Juvenile Xanthogranuloma (Nevoxanthoendothelioma; Xanthoma Multiplex; Juvenile Giant Cell Granuloma) 380
Xanthelasma Palpebrarum 383
Verruciform Xanthoma 384
Necrobiotic Xanthogranuloma (with Paraproteinemia) 385
Hereditary Progressive Mucinous Histiocytosis 386
Hemophagocytic 387
Familial Hemophagocytic Lymphohistiocytosis 387
Histiocytic Cytophagic Panniculitis 388
12 HEMATOPOIETIC DISORDERS 389
Lymphoid Skin Infiltrates 389
Cytomorphology, Major Cell Types 390
T‐Cells 390
B‐Cells 391
Pattern of Small Cell Lymphocytic Infiltrates 392
T‐Cell Pattern 392
B‐Cell Pattern 392
Pseudolymphoma (PL) 393
Nodular B‐Cell PL 393
Lymphadenosis Cutis Benigna (Lymphocytoma Cutis) 393
Differentiation between B‑Pseudolymphoma (PL) and Cutaneous B‐Cell Lymphoma (CBCL) 395
Nodular T‐Cell PL 396
CD30+ Pseudolymphoma in Scabies 396
Papular (Secondary) Syphilis 398
Pseudo‐Mycosis Fungoides (Mycosis Fungoides Simulators) 399
Lymphomatoid Contact Dermatitis 399
Lichen Planus 399
Drug Reactions 400
Early Vitiligo 400
Lichen Sclerosus et Atrophicus 400
Pityriasis Lichenoides Chronica 401
Graft Versus Host Reaction (Acute) 401
Pityriasis Lichenoides et Varioliformis Acuta (PLEVA) 402
Pigmented Purpuric Dermatitis (Lichen Aureus) 403
Lymphocytic Infiltration Jessner-Kanof 404
Cutaneous Mature T‐Cell Lymphoid Neoplasms (CTCL) 405
Mycosis Fungoides, Classic Alibert-Bazin Type 405
Mycosis Fungoides Patch Stage I 405
Mycosis Fungoides Plaque Stage II (CD4+; CD8−) 407
Variant: CD8+ Mycosis Fungoides 409
Mycosis Fungoides Tumor Stage III 409
Large Cell Transformation 410
Simulators and Variants of Mycosis Fungoides: “Parapsoriasis” 411
Simulator: Small Plaque Parapsoriasis (SPP) (Brocq’s Disease, Digitate Dermatosis) 411
Large Plaque Parapsoriasis (LPP) 412
Pigmented Purpuric Mycosis Fungoides 412
Erythrodermic Mycosis Fungoides 412
Folliculotropic (Pilotropic) Mycosis Fungoides 413
Syringotropic Mycosis Fungoides (Syringolymphoid Hyperplasia with Alopecia) 414
Granulomatous Mycosis Fungoides 415
Granulomatous Slack Skin 415
Pagetoid Reticulosis (PR), Unilesional (Woringer-Kolopp) 417
Sézary Syndrome (SS) 418
Variant: Sézary Syndrome, Large Cell Transformation 420
CD30‐Positive Lymphoproliferative Disorders (LPD) of the Skin 423
Anaplastic Large Cell Lymphoma (ALCL) 424
Neutrophil‐Rich (Pyogenic) Anaplastic Large Cell Lymphoma 426
Lymphomatoid Papulosis 427
Differential Diagnosis: Hodgkin’s Lymphoma, Lymphocyte Predominance 429
Subcutaneous Panniculitis‐Like Lymphoma 431
Subcutaneous (Panniculitis-Like; Alpha/Beta) T‐Cell Lymphoma 431
Differential Diagnosis: Subcutaneous (Panniculitis‐Like) Gamma/Delta lymphoma 432
Differential Diagnosis: Lupus Panniculitis (Lupus Profundus) 433
Primary Cutaneous Peripheral Lymphoma (PTL), Unspecified (NOS) 434
Primary Cutaneous CD4‐positive (Acral) Small/Medium‐Sized T‐Cell Lymphoproliferative Disorder 435
Cutaneous Aggressive Epidermotropic CD8‐positive T‐Cell Lymphoma (Berti) 436
Differential Diagnosis: Febrile Ulceronecrotic PLEVA (Mucha-Habermann Disease) 437
Extranodal NK/T‐Cell Lymphoma, Nasal Type (Subcutaneous) 439
Hydroa Vacciniforme‐Like Lymphoma 440
Angioimmunoblastic T‐Cell Lymphoma 441
Cutaneous Mature B‐Cell Lymphoid Neoplasms (CBCL) 443
Cutaneous Marginal Zone B‐Cell Lymphoma (MZL; MALT Type) 444
Variant: Immunocytoma 447
Differential Diagnoses: Multiple Myeloma/Plasmacytoma 448
Primary Cutaneous Follicle Center Lymphoma (FCL) 449
Diffuse Large B‐Cell Lymphoma (DLBCL) 451
Variant: Cutaneous Diffuse Large B‐Cell Lymphoma (Leg Type) 451
Variant: T‐Cell‐Rich B‐Cell Lymphoma (DLBCL) 454
Cutaneous Spindle B‐Cell Lymphoma 455
Extracutaneous B‐Cell Lymphoma (BCL) with Frequent Skin Involvement 457
Mantle Cell Lymphoma 457
Burkitt’s Lymphoma (BL) 458
Lymphomatoid Granulomatosis (Liebow) (LYG) 460
Intravascular Lymphomas 461
Intravascular Large B‐Cell Lymphoma (IV‐LBCL) (Systemic Angioendotheliomatosis) 461
Intravascular T Cell Lymphoma 462
Secondary Skin Involvement in Leukemias/Lymphomas 463
Chronic Lymphocytic Leukemia (CLL) 463
Myeloid and Monocytic Leukemias 464
T‐Zone Lymphoma 466
Adult T‐Cell Leukemia/ Lymphoma (ATLL) 467
Immature Hematopoietic Malignancies 468
Blastic Plasmacytoid Dendritic Cell Neoplasm 468
Precursor Lymphoblastic Leukemia/Lymphoma 470
13 CUTANEOUS CYSTS 471
Cysts with Epithelial Lining 472
Stratified Squamous Epithelium 472
Epidermal (Infundibular) Cysts 472
Variant: Epidermal Proliferating Cyst 473
Variant: Epidermal Cyst with Pigment and Vellus Hairs 473
Vellus Hair Cyst 474
Trichilemmal (Isthmus‐Catagen) Cyst 475
Milia 476
Follicular Hybrid Cyst 477
Hidrocystoma (Cystadenoma) 478
Steatocystoma, Multiplex and Simplex 481
Dermoid Cyst 482
Pilonidal Sinus (Pilonidal Cyst) 484
Non‐Stratified Squamous Epithelium 485
Cutaneous Ciliated Cyst of the Lower Limb 485
Median Raphe Cyst 486
Cysts without Epithelial Lining (Pseudocysts) 487
Oral Mucous Cyst and Superficial Mucocele of the Lip 487
Digital Myxoid Cyst 488
Synovial Cyst (Ganglion) 490
Index 491
