Fibroadenomas are solid and round benign tumors that are made up of both structural (fibro) and glandular (adenoma) tissues. Usually, these lumps are painless and found by the woman rather than a doctor. They feel rubbery and can easily be moved around. Fibroadenomas are the most common type of tumors in women in their late teens and early twenties, and NIH says they occur twice as often in African American women than in other American women.

Fibroadenomas have a typically benign appearance on mammography (smooth, round masses with a clearly defined edge), and they can sometimes be diagnosed with fine needle aspiration. Although fibroadenomas do not become malignant, they can enlarge with pregnancy and breastfeeding. It is essential that a woman who notices a lump or other change in her breast sees her HCP.