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
- Multiple and bilateral fibroadenomas develop in patients receiving Cyclosporin A used after renal transplantation
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

Fibroadenoma: Encapsulated lesion showing lobulated appearance on cut section and with slit like spaces

- 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
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%)
Differential diagnosis –
- Phyllodes tumor – characterized by abundant cellular stroma and leaf like processes projecting into cystic spaces
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

Fattaneh A. Tavassoli, Vincenzo Eusebi. Tumors of mammary gland. AFIP atlas of tumor pathology. Series 4
Vinay kumar, Abul K.Abbas, Nelson Fausto, Jon C. Aster. The Breast. In: Robbins and Cotran Pathologic basis of disease. 8th edition.

Fibroadenoma: Lesion showing compressed cord like ducts. Periductular stroma shows myxoid change (H&E,X50)

Fibroadenoma: Lesion showing fibrous capsule. Underlying the capsule myxoid stroma with compressed ducts are seen (H&E,X100)

Fibroadenoma: Lesion showing compressed cord like ducts. Periductular stroma shows myxoid change (H&E,X100)

FIbroadenoma: Lesion with compressed cord like ducts (intracanalicular pattern). Periductular stroma shows myxoid change and few congested blood vessels (H&E,X50)

FIbroadenoma: Lesion with compressed cord like ducts (intracanalicular pattern). Periductular stroma shows myxoid change and few congested blood vessels (H&E,X100)

Fibroadenoma (Intracanalicular pattern): Compressed cord like ducts (H&E,X200)

Fibroadenoma (Pericanalicular pattern): Rounded ducts surrounded by myxoid stroma (H&E,X200)

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

Multiple and bilateral fibroadenomas develop in patients receiving Cyclosporin A used after renal transplantation

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

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%)

Differential diagnosis –

Phyllodes tumor – characterized by abundant cellular stroma and leaf like processes projecting into cystic spaces

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

Fattaneh A. Tavassoli, Vincenzo Eusebi. Tumors of mammary gland. AFIP atlas of tumor pathology. Series 4

Vinay kumar, Abul K.Abbas, Nelson Fausto, Jon C. Aster. The Breast. In: Robbins and Cotran Pathologic basis of disease. 8th edition.