Definition of Fibroadenoma - breast:

Fibroadenoma of the breast is a benign (noncancerous) tumor.

Causes, incidence, and risk factors:

Fibroadenoma is the most common benign tumor of the breast and the most common breast tumor in women under age 30. Fibroadenomas are usually found as single lumps, but about 10 - 15% of women have several lumps that may affect both breasts.

Black women tend to develop fibroadenomas more often and at an earlier age than white women. The cause of fibroadenoma is not known.