Breast - nonmalignant
Benign tumors / changes
Apocrine adenoma of breast

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 9 January 2016, last major update January 2016

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

PubMed Search: Apocrine adenoma [title] breast
Cite this page: Apocrine adenoma of breast. website. Accessed October 23rd, 2016.
Definition / General
  • Adenoma with apocrine cytology throughout
  • Rare adenoma that is:
    • Composed exclusively of benign apocrine cells (homogeneous)
    • Sharply demarcated from surrounding breast tissue
    • Contains only epithelial proliferative elements
    • Has minimal supportive stroma
Essential Features
  • Nodular mass composed exclusively of apocrine cells without cytological atypia
  • Sharply demarcated from adjacent breast tissue and has minimal stromal component if any
  • Considered benign, excision is curative
  • Cytological atypia, necrosis and invasive features suggest atypical hyperplasia/apocrine malignancy (DCIS / invasive), recommend careful evaluation of the entire lesion
  • Pure breast adenomas with apocrine differentiation were first described by Hertel et al in 1976 (Cancer 1976;37:2891)
  • May represent nodular sclerosing adenosis with apocrine differentiation
Clinical Features
  • Can present as a mass
Prognostic Factors
  • Generally accepted to be benign, however, the number of cases reported is not sufficient to determine the level of risk associated (J Clin Pathol 2007;60:1313)
Case Reports
  • Complete excision is curative
Micro Description
  • By definition, composed exclusively of benign apocrine cells (homogeneous), sharply demarcated from surrounding breast tissue, containing only epithelial proliferative elements, with minimal supportive stroma
  • Localized nodular focus of tubular, papillary and cystic apocrine metaplasia; benign glands have abundant granular eosinophilic cytoplasm, apical luminal blebs and decapitation secretion
  • May contain calcifications (Pathology 2001;33:149)
Micro Images

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Apocrine adenoma

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Apocrine adenoma (6 mm tumor)

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Apocrine adenoma (well circumscribed)

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Tubular apocrine adenoma, skin

Cytology Description
  • Can be cuboidal or flattened, two distinct types seen:
    • Cytoplasm granular and strongly eosinophilic, supranuclear vacuole containing yellow brown pigment (rich in iron / hemosiderin)
      • Globoid and pale nuclei with 1-2 prominent nucleoli (nuclei may become hyperchromatic in flattened epithelium as in tension apocrine cysts)
    • Cytoplasm distinctly foamy with small vacuoles that may coalesce and show lipofuscin pigment in cytoplasm
      • Central nuclei with 1-2 prominent nucleoli
  • Recommend caution to exclude apocrine DCIS or invasive apocrine carcinoma if necrosis / atypia / mitosis present
Positive Stains
  • PAS (with Diastase), EMA, CK8/18, AR (androgen receptor), GCDFP15, GCDFP24 (apolipoprotein D), GCDFP44 (zinc alpha2 glycoprotein)
Negative Stains
Differential Diagnosis