A solid breast lump that isn't cancer that can be found in anyone who has periods.

The cause of fibroadenomas isn't known. They may be linked to hormones that control periods.

A fibroadenoma is round with smooth borders. It can be firm or rubbery. It's painless and moves easily when touched.

A fibroadenoma often needs no treatment. It may need to be watched for changes in size and shape. Treatment may include surgery to remove it.