May also be called: Breast Lump, Benign Breast Tumor

A fibroadenoma (fy-bro-ad-uh-NO-muh) is a solid, noncancerous breast tumor found most commonly in young women.

More to Know

Fibroadenomas are small masses that are generally round and different from surrounding breast tissue. They often feel like marbles within the breast that can be moved around easily under the skin. Fibroadenomas can range in size from those that can only be seen on imaging tests (like a mammogram or ultrasound) to those that are 3 or more inches in diameter. They are most common in women ages 15-35 but may be found in women of any age.

Doctors don’t know what causes fibroadenomas, but a woman can have one or many in one or both breasts. Most fibroadenomas don't cause symptoms, don’t increase a woman’s risk of breast cancer, and don’t need to be removed. However, fibroadenomas that happen with other changes in breast tissue, those that increase in size, or a family history of breast cancer can make cancer more likely. In these cases, or if the woman doesn’t want to worry further about the lump, doctors usually recommend that fibroadenomas be removed.

Fibroadenomas are diagnosed using mammograms, ultrasounds, or biopsies, where a tissue sample is collected from the lump to be examined under a microscope. Treatment options include surgery to remove the lump, or cryoablation, a process that involves freezing and destroying the fibroadenoma.

Keep in Mind

Most fibroadenomas are painless, cause no problems, and can be left in the breast without fear of complications. Fibroadenomas should still be monitored closely, though, to make sure they don’t get bigger. If they do, they can be removed at a later date. In many cases, especially with older women, fibroadenomas may shrink on their own.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.