Fibrocystic changes
Sclerosing adenosis

Topic Completed: 1 January 2015

Minor changes: 20 October 2020

Copyright: 2002-2020,, Inc.

PubMed Search: Sclerosing adenosis [title] breast

Jaya Ruth Asirvatham, M.B.B.S.
Julie M. Jorns, M.D.
Page views in 2019: 13,205
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Cite this page: Asirvatham JR, Jorns JM. Sclerosing adenosis. website. Accessed October 24th, 2020.
Definition / general
  • Low power diagnosis of increase in glandular elements plus stromal proliferation that distorts and compresses glands
  • Preservation of luminal epithelium and peripheral myoepithelium with surrounding basement membrane
  • Adenosis tumor / nodular adenosis:
  • Myoepitheliosis:
    • Rare; sclerosing adenosis with predominance of myoepithelial cells, presents as multifocal microscopic lesions (Am J Surg Pathol 1991;15:554)
    • Cells may have longitudinal nuclear grooves
Clinical features
Radiology description
  • Circumscribed to spiculated mass with architectural distortion
  • Amorphous or pleomorphic clustered microcalcifications
Case reports
  • The presence of sclerosing adenosis alone in a core biopsy does not require surgical excision
Gross description
  • Multinodular, cuts with increased resistance
  • Gritty but no chalky yellow white foci or streaks
Microscopic (histologic) description
  • Low power diagnosis; increase in glandular elements plus stromal proliferation that distorts and compresses glands
  • Maintains lobular architecture at low power with rounded and well defined nodules
  • Centrally is more cellular with distorted and compressed ductules; peripherally has more dilated ductules
  • Often microcalcifications, apocrine metaplasia
  • Two cell layers are present but myoepithelial cells may vary from being prominent to indistinct
  • Also intralobular fibrosis, elastosis and apocrine metaplasia; florid changes are associated with pregnancy
  • Rarely penetrates walls of veins or perineural spaces
  • No necrosis, no pleomorphism
  • Epithelium may be involved by proliferative / atypical lesions or in situ carcinoma
  • Can mimic malignancy:
    • If nonlobulocentric / infiltrative into fat or stroma
    • Conspicuous myoepithelial cells with attenuated epithelial cells can appear like stands of single cells and mimic invasive lobular carcinoma
    • Atypical apocrine metaplasia: nuclear atypia / rare mitosis (Mod Pathol 1991;4:1)
    • Perineural invasion
Microscopic (histologic) images

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AFIP images

Ducts dilated at periphery

Small ducts with microcalcifications

Normal glands in upper right

Retention of
myoepithalial type
cells but loss of
ductal epithelium

Small bland ducts adjacent to nerve

Intraductal papilloma

Invagination into cystic duct


With LCIS and microinvasion (arrows)

Images hosted on other servers:

Small ducts with microcalcifications

Sclerosing adenosis at core biopsy in a 40 year old pregnant woman

Adenosis tumor



Cytology description
Positive stains
Differential diagnosis
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