Breast - nonmalignant
Benign tumors / changes
Ductal adenoma of breast

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 17 November 2015, last major update November 2015

Copyright: (c) 2002-2015,, Inc.

PubMed Search: Ductal adenoma [title] breast
Definition / General
Essential features
  • Well circumscribed benign intraductal proliferation of tubules (no papillary component)
  • May show calcification, hemorrhage, infarction, squamous or apocrine metaplasia or myxoid change
  • May show pseudoinfiltrative pattern (exclude invasion by showing intact myoepithelial marker staining, eg. p63, SMMA)
  • Excision is curative
  • Also called sclerosing papilloma
Clinical Features
  • Presents as palpable lump or mammographic abnormality
  • May resemble carcinoma at imaging, frozen or permanent section (Breast Cancer 2006;13:354)
Radiology description
  • Mammography shows well to ill defined mass with/without calcification
Case Reports
  • Excision is curative
Gross Description
  • Single or multiple rounded lesions
  • Gritty texture and elastic streaks mimic carcinoma
Micro Description
  • Well circumscribed, bounded by dense fibrous wall of medium to large duct from which it arises
  • Composed of proliferating epithelial tubules but no papillary component (or it would be a papilloma)
  • Has both epithelial and myoepithelial cell types
  • May have pseudoinfiltrative pattern due to compressed tubules, which resembles invasion in a core biopsy
  • Also focal dilated tubules, epithelial hyperplasia, cysts, squamous or apocrine metaplasia, myxoid change, calcification
Micro Images

Images hosted on PathOut server:

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Central fibrosis, peripheral bland ducts

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Nodular lesion, primarily spindle cells

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Spindle cells with residual ducts

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Spindled myoepithelial cells around peripheral duct

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Ducts lined by apocrine cells

Images hosted on Other servers:

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Ductal adenoma, partially sclerosed

Cytology Description
  • May resemble lactating adenoma, intraductal papilloma or carcinoma
  • Highly cellular with monolayered sheets of ductal cells with cytoplasmic vacuoles that are small and punched out
  • Numerous large fragments of purple stroma are adjacent to epithelial cells, forming finger-like hyaline structures or globules between cells
  • Nuclei are round / oval with bland chromatin
  • Occasional cells have enlarged nuclei with prominent nucleoli
  • Also naked oval nuclei (Diagn Cytopathol 1994;10:143, Diagn Cytopathol 1995;13:252)
Positive Stains
Negative Stains
Differential Diagnosis