Common benign tumours of stromal/epithelial tissue. They are small and mobile within the breast tissue.

Epidemiology:

• 12% of all breast masses
• Over a 2 year period up to 30% will get smaller
• Associated with younger patients (15-35)

Pathology

• Fibroadenomas are normally hormone dependant, so may increase in size with pregnancy and decrease or involute after the menopause.
• Fibroadenomas are not cancerous and are not usually associated with an increased risk of developing breast cancer. Complex fibroadenomas and a positive family history of breast cancer may indicate a higher risk.

PC

On examination, fibroadenomas are:

• Painless (can present with tenderness)
• Smooth
• Round
• Well circumscribed (well-defined borders)
• Firm
• Mobile (moves freely under the skin and above the chest wall) - ‘breast mice’
• Usually up to 3cm diameter