Fibroadenomas (fy-broe-ad-uh-NO-muhz) are solid, noncancerous breast lumps that occur most often in women between the ages of 15 and 35.
A fibroadenoma might feel firm, smooth, rubbery or hard and has a well-defined shape. Usually painless, it might feel like a marble in your breast, moving easily under your skin when examined. Fibroadenomas vary in size, and they can enlarge or shrink on their own.
Fibroadenomas are among the most common noncancerous (benign) breast lumps in young women. Treatment might include monitoring to detect changes in size or feel, a biopsy to evaluate the lump or surgery to remove it.