Fibroadenoma.

FIBROADENOMA
  • Common benign neoplasm of female breast originating from Terminal duct lobular unit (TDLU)
  • Fibroadenoma develop as a result of unopposed estrogenic stimulation. Size of fibroadenoma increases during lactation and pregnancy
  • Age – common in younger age but can occur at any age group
  • clinical presentation –
    • Painless, solitary, well circumscribed, firm and freely mobile mass in the breast
    • Multiple fibroadenomas are seen in 1/4th cases
  • Mammography 
    • Presents as mammographic density or calcifications which can be small clustered or large “Popcorn” calcifications
  • Morphology 
    •  Gross
      • usually measures 1-5cm but can be very of very large size also
      • Well circumscribed, grayish white firm rubbery nodule
      • cut section – uniformly gray white fleshy with small slit like spaces and gelatinous appearance
    • Microscopy 
      • Tumor consists of proliferating epithelial and mesenchymal components
      • Stroma proliferates around tubular ducts (pericanalicular pattern) or compressed cleft like ducts (Intracanalicular pattern)
      • Ducts are lined by luminal epithelial cells and outer myoepithelial cells. Luminal epithelial cells may show hyperplasia. Other changes like atrophic change or apocrine change or squamous metaplasia can also occur
      • Stroma shows abundant hyalinization and myxoid change.
      • Stromal alterations which can occur are 
        • Calcifications
        • Adipose tissue
        • Chondroid or osseous metaplasia
        • Smooth muscle metaplasia
        • Bizarre multinucleated giant cells 
      • Infarction may develop during pregnancy or lactation

               Pericanalicular pattern

 

               Intracanalicular pattern

 

  • Immunohistochemistry – 
    • Epithelial cell are positive for – EMA, CK7, CAM5.2, ER (Variable), PR (more frequently positive)
    • Myoepithelial cells are positive for – SMA, Calponin, Caldesmon, p63
    • Stromal cells are positive for -SMA, CD 34, Factor XIIIa (5% to 20%)
  • Prognosis and treatment –
    • Fibroadenomas constitute minor risk of 1.6 to 2.17 times for the development of breast carcinoma.
    • Treatment is surgical removal of the tumor
References
  1. Fattaneh A. Tavassoli, Vincenzo Eusebi. Tumors of mammary gland. AFIP atlas of tumor pathology. Series 4
  2. Vinay kumar, Abul K.Abbas, Nelson Fausto, Jon C. Aster. The Breast. In: Robbins and Cotran Pathologic basis of disease. 8th edition.