Previously fibroadenomas were considered to be benign neoplasms of the breast. However, as they do not develop from a single cell and are under normal hormonal control they are best considered as an aberration of normal breast development (ANDI).
Most common cause of a discrete breast lump in young women.
Peak 25–35 years, but can occur any time from menarche to menopause.
Fibroadenomas are usually solitary lesions that result from a hyperplastic or proliferative process in a single terminal ductal unit. Fibroadenomas are under hormonal control, they may enlarge during pregnancy and involute at menopause.
Patients (normally young women) present with a smooth, firm, painless nodule that is welldemarcated and freely mobile (breast mouse). Fibroadenomas may be multiple in 10–15%.
Juvenile fibroadenoma is a rare subtype that occurs in female adolescents and grows rapidly. Histologically they resemble common fibroadenomas and are benign. However, local recurrence can only be prevented by complete excision.
An encapsulated rubbery white lesion with a glisten-ing cut surface. It consists of a fibrous connective tissue component and abnormally proliferated ducts and acini (adenoma) in varying proportions.
Investigation of any breast lump involves a triple assessment consisting of clinical examination, imaging normally by ultrasound as patients are young and sampling by core biopsy or fine needle aspiration.
If confirmed as a fibroadenoma on triple assessment, small lesions may be left unless the patient requests excision. Larger lesions and those with equivocal histology should be excised.
Untreated only 10% of fibroademonas increase in size over a 2-year period most of which occur in teenage women. It is thought that most fibroadenomas involute if left untreated.