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: 5 October 2016, last major update May 2015

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Apocrine tubular adenoma

Cite this page: Apocrine tubular adenoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumornonmelanocyticapocrinetubularadenoma.html. Accessed December 6th, 2016.
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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Mimicks basal cell carcinoma

Gross Description
  • Firm, slow growing, dermal or cutaneous skin colored nodule
Micro 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
Micro Images

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Intradermal nodule

Tubules filled with eosinophilic secretion lined by apocrine epithelium, with papillary projections into lumina



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