Fibroadenomas of the breast are benign growths that occur throughout the age spectrum. They are most commonly seen in younger women, with a median age of patients of 25 years. Of all benign breast lesions, fibroadenomas account for the largest amount.

These growths are proliferative type lesions without atypia. Etiology is unknown but may be related to hormones and hormone use. However, postmenopausal patients also can develop new fibroadenomas. Lifetime risk is estimated to be about 10%. Incidence has been seen to decrease with increasing age.

Fibroadenomas are often asymptomatic and found incidentally during routine examinations, although a patient may present with a complaint of a newly noted unilateral, small (1-2 cm), firm, mobile mass.