Update on Breast Fibroadenoma

In GP-bulletin by Karina Cox

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  • Fibroadenomas are benign and composed of both stromal and epithelial elements.
  • They are more common in women of childbearing age.
  • As many as 10% of women have fibroadenomas and of them, 10-15% may have multiple fibroadenomas (in either breast).
  • The natural history of fibroadenomas means that approximately 50% will spontaneously disappear, 25% will stay the same and 25% will increase in size.
  • Less than 1% of fibroadenomas presenting as a palpable lump will have atypia, in-situ or invasive tumour within the epithelial component.
  • Less than 3% of growing fibroadenomas will contain a malignancy in the epithelial component or be an undiagnosed phyllodes tumour.

Fibroadenomas typically present as a new breast lump and should be referred to a breast clinic. A previously diagnosed fibroadenoma that is increasing in size should also be referred to a breast clinic.

  • In the breast clinic, mammography if age appropriate and ultrasound examination will be performed with a core biopsy of the lump if the patient is older than 25 or there are indeterminate clinical/ radiological features.
  • Core biopsy is safe and reliable for diagnosis as long as the result is concordant with clinical presentation and imaging features.

Most patients diagnosed with a fibroadenoma can be reassured. Surgical excision may be recommended in cases where; a cellular fibroadenoma is found on biopsy (can be difficult to distinguish from a benign phyllodes tumour) or the fibroadenoma is growing rapidly. Pain is a relative indication, as removal may not guarantee relief of symptoms.