General
=========================================================================

• Defined as the presence of apocrine cytology in a recognisable lobular unit associated with sclerosing adenosis (J Clin Pathol 2007;60:1313)

Terminology
=========================================================================

• The terminology "apocrine adenosis" has also been used to refer to Adenomyoepithelial adenosis, a different lesion
• Use of the term "apocrine change in sclerosing adenosis" has been suggested to avoid confusion (J Clin Pathol 2007;60:1313)

Atypical apocrine adenosis
=========================================================================

• Defined as 3 fold variation in nuclear size
• Uncommon lesion
• Average age of women is 59 years
• A study of 37 patients showed no increased risk for carcinoma, as previously suggested (Arch Pathol Lab Med 2012;136:179)

Micro description
=========================================================================

• Cells with apocrine metaplasia have abundant eosinophilic cytoplasm with bright eosinophilic granules that are PAS positive
• The apocrine cells have round nuclei and may show nuclear pleomorphism (>3 fold in atypical variant); a central eosinophilic nucleolus is generally seen
• Rare multinucleation may be observed and is not considered atypical
• Rare to no mitosis
• No necrosis
• Can be associated with radial scars

Micro images
=========================================================================

AFIP: circumscribed lesion

Within a lobule

     

Expansion of lobular units with marked apocrine metaplasia ("B" is low power location)

 

With sclerosing adenosis

AFIP: appears infiltrative

Calcification

Highly cellular and tumefactive growth pattern

AFIP: Ducts lined by apocrine cells with large nuclei and prominent nucleoli

AFIP: Cells have vacuolated cytoplasm, large nuclei and prominent nucleoli

Androgen receptor positive

   

With atypia, contributed by Dr. Semir Vranic

   

With atypia: 3x variation in nuclear size

Cytology description
=========================================================================

• Often highly cellular
• Cells have apocrine metaplasia with prominent nucleoli and pleomorphism, possibly resembling carcinoma, but minimal hyperchromasia
• Naked nuclei are present (Diagn Cytopathol 2007;35:296)

Positive stains
=========================================================================

• EMA, GCDFP-15 (Am J Surg Pathol 1993;17:99)
• Androgen receptor (J Clin Pathol 1999;52:838), PAS for basement membrane (Mod Pathol 1993;6:318)

Negative stains
=========================================================================

• ER, PR

Electron microscopy description
=========================================================================

• Distinct basal lamina present

Differential diagnosis
=========================================================================

• Apocrine carcinoma: malignancy should be obvious
• Cancerization of lobule by apocrine DCIS: Architectural patterns of DCIS typically also present (eg. comedo, cribriform, etc.); mitosis and necrosis usually identified
• Microglandular adenosis: glands are smaller, more regular; no myoepithelial cells
• Tubular adenosis: haphazard proliferation of elongated tubules

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).