Skin nonmelanocytic tumors
Adnexal tumors - apocrine sweat glands
Apocrine tubular adenoma

Author: Aravindhan Sriharan, M.D. (see Authors page)
Editor: Sara Shalin, M.D.

Revised: 14 September 2018, last major update May 2015

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Apocrine tubular adenoma

Cite this page: Sriharan, A. Apocrine tubular adenoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumornonmelanocyticapocrinetubularadenoma.html. Accessed September 25th, 2018.
Definition / general
  • Benign dermal adnexal neoplasm of apocrine derivation
  • Most common location is scalp, typically in women (M:F ratio is 1:2)
  • Also called apocrine adenoma, tubular adenoma, tubulopapillary hidradenoma, papillary tubular adenoma
  • Associated with organoid nevus, nevus sebaceus of Jadassohn and syringocystadenoma papilliferum (SCAP)
  • Rarely occurs in nose, eyelid, leg, trunk, axilla, chest, external auditory meatus, cheek, vulva
  • Clinically asymptomatic, sometimes smooth, sometimes irregular, well-defined nodule
  • Usually < 2 cm but reported up to 7 cm
Case reports
Treatment
  • Complete excision is curative
  • Malignant transformation is rare
Clinical images

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Mimics basal cell carcinoma

Gross description
  • Firm, slow growing, dermal or cutaneous skin colored nodule
Microscopic (histologic) description
  • Well circumscribed dermal neoplasm that may extend into subcutis
  • Lobular pattern of dermal and subcutaneous tubular apocrine structures often encased by a fibrous, sometimes hyalinized stroma
  • Lobules have dilated, variably sized tubules lined by two layers of epithelial cells
  • Pseudopapillae are common, but true papillae are more often associated with SCAP
  • Decapitation secretion by apical layer
  • Cuboidal to columnar cells with eosinophilic cytoplasm and round bland nuclei
  • Often hyaline and clear cell change
  • May show cyst formation with papillae or pseudopapillae protruding into the lumen
  • Variable overlyng epidermal hyperplasia
  • Rare connection with overlying epidermis
Microscopic (histologic) images

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Intradermal nodule

Cystically dilated tubules in hyalinized background

Tubule morphology

Smooth nuclear contours and open chromatin

Positive stains
  • EMA, CAM5.2 (luminal surface of tubules), CEA (luminal surface of tubules)
  • SMA (outer tubules), GCDFP-15 (focal diffuse cytoplasmic), CK7
  • S100 (myoepithelial layer)
Electron microscopy description
  • Tall columnar cells on basal lamina forming acini
  • Cells lining tubules have luminal villi and apical pinching
  • Conspicuous mitochondria, prominent golgi
  • Lipid rich cytoplasmic secretory vacuoles
  • Decapitation secretion (J Am Acad Dermatol 1984;11:639)
Differential diagnosis
  • Apocrine cystadenoma: more dilated, cystic spaces rather than tubules
  • Hidradenoma papilliferum: often has complex arborizing papillae, with more closely arranged tumor cells and glands
    • Limited to female genital region
  • Papillary apocrine carcinoma: more cytologic atypia, irregular nuclear contours and a higher mitotic rate
  • Papillary eccrine adenoma: classically has features of eccrine rather than apocrine derivation; lacks decapitation secretion; different clinical presentation and distribution
  • Syringocystadenoma papilliferum:
    • Usually connects to epidermis
    • Fibrovascular cores within papillary structures
    • Plasma cells within stroma
    • Tubular apocrine adenoma may be a variant