Breast - nonmalignant
Benign tumors / changes
Fibroadenoma

Author: Hind Nassar, M.D. (see Authors page)

Revised: 4 August 2017, last major update March 2014

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Fibroadenoma of the breast [title]

Cite this page: Fibroadenoma. PathologyOutlines.com website. http://pathologyoutlines.com/topic/breastfibroadenoma.html. Accessed November 20th, 2017.
Definition / general
  • Benign biphasic tumor with epithelial and stromal components
Epidemiology
  • Usually women age 30 years or less
Sites
  • Often in upper outer quadrant
Etiology
  • Usually considered neoplastic; some believe it results from hyperplasia of lobular components
Clinical features
Radiology description
  • Xray: heavy, coarse calcifications
Radiology images

Images hosted on PathOut server:

Mammogram, contributed by Dr. Mark R. Wick

Case reports
Treatment
  • Excision (completely excise if 4 cm or more, enlarging over time and infiltrative border; after core biopsy, excise if cellular stroma found and phyllodes tumor cannot be excluded)
  • May "recur" if adjacent fibroadenomatous hyperplasia is present
  • Cryoablation (Am J Surg 2005;190:647)
  • Anti-estrogens (World J Surg 2007;31:1178)
Gross description
  • Sharply circumscribed with smooth, rounded border, freely movable spherical nodule, usually 3 cm or less
  • Gray white, bulging cut surface with numerous slits
  • 20% multifocal
Gross images

Images hosted on PathOut server:

Contributed by Dr. Mark R. Wick



Images hosted on other servers:

Various images

Multiple fibroadenomas


Well circumscribed mass

Microscopic (histologic) description
  • Rounded contour, overgrowth of fibrous and glandular tissue
  • Intralobular stroma (delicate, cellular, myxoid or fibrotic) encloses glandular spaces; may infarct, become inflamed, calcify
  • Pericanalicular: open glandular spaces vs intracanalicular: compressed glandular spaces (no clinical significance to this distinction)
  • Glands have cuboidal / low columnar epithelium and adjacent myoepithelium but no atypia
  • 15% have apocrine metaplasia
  • May have myxoid change (suggests Carney syndrome), sclerosing adenosis, epithelial hyperplasia or other fibrocystic change
  • May have adjacent fibroadenomatous change
  • Rarely has pleomorphic, bizarre multinucleated giant cells (Arch Pathol Lab Med 2000;124:1721, Diagn Pathol 2008;3:33, Am J Surg Pathol 1986;10:823, Arch Pathol Lab Med 1994;118:912), squamous metaplasia, smooth muscle or adipose tissue, metaplastic cartilage, DCIS or LCIS
  • Fibroadenoma phyllodes: rarely has focal leaf-like processes but otherwise typical fibroadenomatous stroma
  • No necrosis, no elastic tissue, no anaplasia, no mitotic figures
Microscopic (histologic) images

Scroll to see all images:


Images hosted on PathOut server:

Contributed by Dr. Mark R. Wick

Containing DCIS, contributed by Dr. Mark R. Wick

Atypical stromal cells


Epithelial hyperplasia

With LCIS


With adenosis

Smooth muscle

Squamous metaplasia



Images hosted on other servers:

Fibroblastic stroma surrounding compressed ducts


Intracananlicular pattern

Pericanalicular pattern

Mild hypercellularity

With apocrine change


Infarcted fibroadenoma, contributed by Dr. Semir Vranić, University of Sarajevo (Bosnia)

With cystic changes


Epithelial hyperplasia

With atypical lobular hyperplasia

With colloid (mucinous) carcinoma


With DCIS

With infiltrating ductal carcinoma


Fibroadenoma with LCIS and invasive lobular carcinoma (contributed by Semir Vranić, MD)


Core biopsies

Digital fibroma-like inclusions

Various immunostains

Fig 2: Fibroadenoma
Fig 3: Giant cells
Fig 4: Vimentin

LMP1+ (EBV+) tumor

ER-beta staining of stromal cells (fig a - b)


With papillary carcinoma

Pericanalicular

Myxoid stroma

Bizarre stromal giant cells


Stromal edema

Virtual slides

Images hosted on other servers:

Fibroadenoma

Cytology description
Cytology images

Images hosted on other servers:

Various images


             

Fig 1: Multiple masses in mammogram
Fig 2, 3: FNA shows sheets and clusters of ductal cells and
myoepithelial cells with background myxoid stroma
Fig 4: Classic features at core biopsy

Positive stains
Stromal cells
Epithelial cells
Electron microscopy description
  • Basal lamina around epithelial and endothelial cells
Molecular / cytogenetics description
  • Clonal chromosomal aberrations in 20%
Videos


             Fibroadenoma
Differential diagnosis