Breast - nonmalignant
Fibrocystic disease
Apocrine metaplasia of breast

Author: Hind Nassar, M.D.

Revised: 9 November 2018, last major update April 2010

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

PubMed Search: Apocrine metaplasia [title] breast

Cite this page: Nassar, H. Apocrine metaplasia of breast. website. Accessed December 15th, 2018.
Definition / general
  • Common nonneoplastic condition as part of (nonproliferative) fibrocystic changes
  • Common in women > 30 years of age but most common in postmenopausal women
  • Not known, may be related to hormonal imbalances
Clinical features
  • There are no specific clinical features in the majority of cases
  • In some cases, lesions with complex papillary and cystic architecture can present as a mass
Prognostic factors
  • No treatment is necessary if isolated finding
Gross description
  • No specific gross findings
Microscopic (histologic) description
  • Cells resemble apocrine sweat glands; are enlarged with abundant eosinophilic cytoplasm and apical snouts, often supranuclear vacuoles, medium sized round nuclei with prominent nucleoli
  • Changes may be partial / incomplete, usually involving a cystic space
  • Usually forms a flat or micropapillary epithelium; in rare cases the lesion can be complex cystic and papillary (with benign cytological features)
  • May have more atypical features in sclerosing adenosis
  • Highly complex architecture with cytologic atypia should be categorized as ADH or DCIS
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Dr. Abdulaziz M. Ahmed

Fibrocystic Disease


Apocrine metaplasia

With epithelial hyperplasia

Images hosted on other servers:

Apocrine metaplasia

With epithelial hyperplasia

Papillary proliferation

Strong androgen receptor staining

Negative for progesterone
receptor (positive internal
control in normal breast
at upper left)

Highly complex papillary apocrine change

Various images

Cytology description
  • Atypical apocrine metaplasia with signet ring cells (such as from sclerosing papilloma) may resemble mucinous carcinoma (Acta Cytol 2002;46:749)
Positive stains
Negative stains
Electron microscopy description
  • Numerous mitochondria in the cytoplasm
Molecular / cytogenetics description
Differential diagnosis