Breast - nonmalignant
Sclerosing adenosis

Topic Completed: 1 January 2015

Revised: 15 January 2019

Copyright: (c) 2002-2019,, Inc.

PubMed Search: Sclerosing adenosis [title] breast

Jaya Ruth Asirvatham, M.B.B.S.
Julie M. Jorns, M.D.
Page views in 2018: 11,111
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Cite this page: Asirvatham JR Sclerosing adenosis. website. Accessed August 24th, 2019.
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

Scroll to see all images:

AFIP images:

Fig 52: Ducts dilated at periphery

Fig 56 - 57: Small ducts with microcalcifications

Fig 70: Normal glands in upper right

Fig 58: Retention of
myoepithalial type
cells but loss of
ductal epithelium

Fig 59: Small bland ducts adjacent to nerve

Fig 53, 55: Intraductal papilloma

Fig 54: Invagination into cystic duct

Fig 194, 195, 197: With LCIS

Fig 198, 199: With LCIS and microinvasion (arrows)

Images hosted on other servers:

Low power

Small ducts with microcalcifications

Late stage; fibrosis and decreasing acini

Resembles microglandular adenosis

Myoid differentiation

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

In sentinel nodes

Various images

Adenosis tumor


Smooth muscle actin


Cytology description
Positive stains
Differential diagnosis
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