Apocrine and eccrine adnexal tumors

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1 Apocrine and eccrine adnexal tumors Timothy McCalmont, MD University of California San Francisco, CA ECCRINE TUMORS Generally uncommon, because the sweat apparatus has little proliferative potential (hyperproliferation precedes mutagenesis in oncogenesis) Eccrine tumors Poroma Syringoma and syringomatous ca Poroma and porocarcinoma Hidradenoma and hidradenoca Papillary adenoma and papillary adenoca 1

2 Poroma Patterns Juxtaepidermal (epidermal and dermal poroma) Intraepidermal (hidroacanthoma simplex) Intradermal (dermal duct tumor) 2

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4 Poroma Hallmarks Small cuboidal (poroid) cells Prominent ductal differentiation Highly vascular stroma Necrosis en masse, when large Poroma Eccrine or apocrine When volar, manifest as a vascular nodule: true eccrine poroma Poroma Eccrine or apocrine When volar, manifest as a vascular nodule: true eccrine poroma When within nevus sebaceus or within axillary skin: apocrine poroma Papillary adenoma 4

5 Papillary adenoma Papillary adenocarcinoma Favors acral sites Not aggressive, it s an adenoma Induced by BRAF V600E mutation The differential is... 5

6 Papillary adenocarcinoma The successor term to aggressive papillary digital adenoma May be tubular or tubulopapillary rather than strictly papillary Elevated mitotic index Potential for secondary spread APOCRINE TUMORS Apocrine and eccrine lineage is not easily judged by standard microscopy Apocrine differentiation often occurs jointly with follicular and sebaceous attributes, thus diverse! Strictly apocrine tumors Syringoma Poroma Hidradenoma Apocrine adenomas, including hidradenoma papilliferum and syringocystadenoma Spiradenoma and cylindroma And corresponding carcinomas Tumors with mixed apocrinefollicular-sebaceous differentiation Chondroid syringoma Microcystic adnexal carcinoma 6

7 Syringoma Commonly periorbital, sometimes acra Small with associated sclerosis Eccrine or apocrine 7

8 Syringoma Hallmarks Numerous small nests or ducts, often with a central cuticle Tadpole or comma-shaped nests Stromal desmoplasia Hidradenoma A poroma knock-off Commonly with clear cells (clear cell hidradenoma) Solid or cystic (solid/cystic hidradenoma) Eccrine or apocrine 8

9 I Give Up: acrospiroma & nod. hidradeoma Bridging designations that encompass poroma and hidradenoma for those who prefer to lump rather than split Hidradenoma Hallmarks Cuboidal cells with pale cytoplasm, larger than those of poroma Limited ductular differentiation Solid or cystic or both Stromal sclerosis 9

10 Apocrine adenomas Papillary adenoma Tubular adenoma Tubulopapillary adenoma Periocular (apocrine) adenoma Hidradenoma papilliferum Syringocystadenoma Hidradenoma papilliferum An adenoma with a circumscribed frond-like pattern Common to genital skin or the axillary vault Utterly unrelated to conventional hidradenoma 10

11 Syringocystadenoma papilliferum Common to the scalp Commonly secondary in association with nevus sebaceus Syringocystadenoma papilliferum 11

12 Apocrine adenomas Hallmarks: Papillary morphology Associated myoepithelium Decapitation secretion Stromal plasma cells Spiradenoma and cylindroma Tumors with primitive glandular and limited ductal differentiation Simply spiradenoma (not eccrine spiradenoma) Apocrine spiradenoma! Spiradenoma, prototypically Non-volar Coexists with cylindroma Occurs in the breast 12

13 Spiradenoma, prototypically A puzzle with few pieces arrayed in non-complex fashion A trabecular pattern internal pattern with dark and pale cells Scattered lymphocytes Cylindroma, prototypically 13

14 Cylindroma, prototypically A puzzle with 500 interlocking pieces arrayed in a complex pattern Associated basement membrane material, either in droplets within nests or circumferentially around nests Spiradenoma and cylindroma, in reality Mixed tumor (chondroid syringoma) Spiradenocylindroma Hamartoma-like with ductal epithelial structures and equal proportions of mesenchyme Stroma may be chondroid, myxoid, fibrous, adipocytic, or a mix AKA pleomorphic adenoma 14

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16 True chondroid syringoma: cartilaginous and syringeal Microcystic adnexal carcinoma (MAC) Rare, but not uncommon as an adnexal carcinoma Common to the head/neck Slow growing, often back-dated to teens, 20s, or 30s MAC Typified by mixed follicular and ductal differentiation Cytologically bland but architecturally malignant Infiltrative Prone to misdiagnosis in superficial biopsies 16

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19 MAC Hallmarks Poor circumscription with deep infiltration, often of nerve or muscle Stromal desmoplasia Microcystic follicular infundibular differentiation Syringoma-like ductal differentiation (Think of syringomatous carcinoma as half a MAC) Timothy H. McCalmont, M.D. Past misguided notions Eccrine poroma rather than poroma being eccrine or apocrine Calling spiradenoma eccrine while calling cylindroma apocrine Microcystic adnexal carcinoma shows mixed follicular and eccrine differentiation Factors crucial to understanding adnexal lineage Embryology Syndromic tumors Histomorphology 19

20 Embryology Folliculosebaceousapocrine unit 20

21 The progeny of nevus sebaceus Syringocystadenoma (apocrine) Trichoblastoma (follicular) Trichilemmoma (follicular) Sebaceous adenoma (sebaceous) Tubular adenoma (apocrine) Poroma (apocrine, when occurring in nevus sebaceus) 21

22 Syndromic tumors The lesson of Brooke-Spiegler Spiradenoma, cylindroma, and trichoepithelioma all commingle in a syndrome, and all are of related lineage (folliculosebaceous-apocrine lineage) Histomorphology Light microscopic pattern Immunophenotype (immunohistochemistry) Enzyme expression (histochemistry) Ultrastructure (electronmicroscopy) 22

23 How do we know what we know? Follicular attributes Germinativ) cells with adjacent mesenchymal cells (resembling the bulb and papilla) Matrical (shadow) cells Pale outer sheath cells with adjacent thickened membrane Trichohyaline granules Sebaceous attributes Vacuolated cytoplasm Nuclear scalloping 23

24 Apocrine attributes Decapitation? Cuticulated ducts? Clear cells? Eccrine attributes Cuticulated ducts? Clear cells? Immunohistochemical reagents Carcinoembryonic antigen (CEA) S100 protein Gross cystic disease fluid protein (GCDFP-15) Epithelial membrane antigen (EMA) Anti-keratins What staring at slides tells us: We can define follicular and sebaceous differentiation, often in laser-like fashion 24

25 What staring at slides tells us: We can define follicular and sebaceous differentiation, often in laser-like fashion Sadly, we cannot precisely identify apocrine and eccrine lineage What staring at slides tells us: We can define follicular and sebaceous differentiation, often in laser-like fashion Sadly, we cannot precisely identify apocrine and eccrine lineage With your next eccrine carcinoma, be a little skeptical 25