Breast nonmalignant
Nonneoplastic changes
Sclerosing lobular hyperplasia

Topic Completed: 1 November 2015

Minor changes: 4 September 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Breast sclerosing lobular hyperplasia

Cansu Karakas, M.D.
Page views in 2019: 2,092
Page views in 2020 to date: 815
Cite this page: Karakas C. Sclerosing lobular hyperplasia. website. Accessed May 29th, 2020.
Definition / general
  • Benign proliferative tumor of young women, characterized by enlarged lobules with an increased number of acini and variable interlobular fibrosis
Clinical features
Radiology description
  • Mammography: nonspecific findings of well defined mass or normal mammogram
  • May be obscured by relatively denser glandular tissues in younger patients
  • Sonography: usually hypoechoic mass (Eur Radiol 2003;13:1645)
  • Microcalcifications may be seen occasionally, especially in older women
Prognostic factors
Case reports
Gross description
  • Relatively well circumscribed, soft to firm, nodular mass
  • Cut surface is solid, gray white with a few scattered slit-like spaces
  • Usually lacks the sharp demarcation and whiteness of a fibroadenoma
  • No hemorrhage or necrosis
Gross images

Case of the Week #62

White, firm and homogeneous

Microscopic (histologic) description
  • Well circumscribed but not encapsulated
  • Enlarged breast lobules with an increased number of acini
  • The acini have the normal breast architecture with distinct single layers of epithelial and myoepithelial cells
  • Intralobular stroma is collagenized, with variable interlobular stromal fibrosis
  • Sclerosing lobular hyperplasia is found in surrounding breast tissue of 50% of fibroadenomas (Hum Pathol 1984;15:336)
  • No / rare mitotic figures, no atypia
Microscopic (histologic) images

AFIP images

Well circumscribed

Case of the Week #62

Large lobules, increased ductules, dense stroma with collagenous fibrosis, bland and acellular

Prominent fibroblastic and myofibroblastic proliferation forming slit-like spaces, resembles pseudoangiomatous stromal hyperplasia

Dense interlobular fibrosis has glomeruloid pattern with trichrome stain

CK8+ lobules

Myoepithelial cells are calponin+

Images hosted on other servers:

Well circumscribed

Large lobules

Dense keloid-like

Normal lobular architecture

Cytology description
  • Cytology by itself is not diagnostic
  • Uniform round / oval ductal epithelial cells in monolayered sheets and round acinar clusters; no atypia (Diagn Cytopathol 2004;31:340, Cytojournal 2006;3:8)
  • Occasional stromal fragments and a fair number of bare nuclei
  • No branched tubular fragments
  • Complete absence of stromal fragments and rarity of bare nuclei are not consistent features of sclerosing lobular hyperplasia and may not help to distinguish from fibroadenoma
Cytology images

Images hosted on other servers:

FNA, moderately cellular

Scattered fragments of stroma

Round to oval nuclei

Positive stains
Differential diagnosis
  • Fibroadenoma: more clearly demarcated; irregular proliferating elongated and distorted ducts and loose cellular stroma; both are treated similarly
  • Hamartoma: clearly demarcated, lacks the enlarged lobular architecture of sclerosing lobular hyperplasia; may contain fatty and myoid component
  • Tubular adenoma: tight packing of acinar structures (no or few ductal elements), with little intervening stroma
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