Fibroadenoma - Benign disorders of the breast

Fibroadenoma

Definition

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).

Incidence

Most common cause of a discrete breast lump in young women.

Age

Peak 25–35 years, but can occur any time from menarche to menopause.

Pathophysiology

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.

Clinical features

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.

Macroscopy/microscopy

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.

Investigations

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.

Management

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.

Prognosis

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.