Breast
Other benign tumors
Apocrine adenoma
Author: Monika Roychowdhury, M.D.
Last author update: 1 January 2016
Last staff update: 16 December 2021
Copyright: 2002-2025, PathologyOutlines.com, Inc.
PubMed Search: Breast [title] apocrine adenoma
Table of Contents
Definition / general | Essential features | Terminology | Etiology | Clinical features | Prognostic factors | Case reports | Treatment | Microscopic (histologic) description | Cytology description | Positive stains | Negative stains | Differential diagnosis | Additional referencesCite this page: Roychowdhury M. Apocrine adenoma . PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastapocrineadenoma.html. Accessed January 11th, 2025.
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
Terminology
- Pure breast adenomas with apocrine differentiation were first described by Hertel et al. in 1976 (Cancer 1976;37:2891)
Etiology
- 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
- 45 year old man with 3 mm tumor (Arch Pathol Lab Med 2003;127:1498)
- 47 year old woman with mammographically detected tumor (WV Med J 2008;104:16)
- 53 year old woman with coexisting invasive ductal carcinoma (Pathol Res Pract 2007;203:809)
Treatment
- Complete excision is curative
Microscopic (histologic) 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)
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
- Cytoplasm granular and strongly eosinophilic, supranuclear vacuole containing yellow brown pigment (rich in iron / hemosiderin)
- Recommend caution to exclude apocrine DCIS or invasive apocrine carcinoma if necrosis / atypia / mitosis present
Positive stains
Differential diagnosis
- Apocrine DCIS: extensive proliferation, marked nuclear pleomorphism, multiple prominent nucleoli and comedo-type necrosis
- Atypical apocrine hyperplasia: architectural atypia such as Roman bridges, cribriform patterns and multiple papillary fronds; no connective cores or cytological atypia such as three fold variation in nuclear size and marked pleomorphism
- Fibroadenoma: prominent proliferating stromal component, compressed epithelium in intracanalicular variant
- Prominent apocrine changes as a part of fibrocystic changes: not nodular, no distinct mass
- Well differentiated apocrine carcinoma: has obvious malignant changes
Additional references
