Fibroadenomas of the breast usually appear in young women, including adolescents. The cause is unknown. In adults, fibroadenomas of the breast may decrease in size over time, but in adolescents, they tend to continue to grow.
Fibroadenomas of the breast may be mistaken for breast cancer, but they are not. Some fibroadenomas do not appear to increase the risk of breast cancer. However, complex fibroadenomas (which have many components, such as cysts, scar tissue, and hardened lumps) may increase the risk slightly.
The lumps are painless and easy to move, and they have clearly defined edges that can be felt during breast self-examination. These characteristics indicate to a doctor that the lumps are less likely to be cancerous. Nonetheless, to be sure that they are not cancerous, the doctor usually removes part or all of the lump to be examined under a microscope (biopsy). A local anesthetic is used.
Fibroadenomas of the breast are usually removed if they grow or cause symptoms. Because fibroadenomas in adolescents tend to grow, they should be removed. However, fibroadenomas often recur. If several lumps have been removed and found to be noncancerous, a woman and her doctor may decide against removing new lumps that develop to avoid having repeated removals. Regardless of whether the fibroadenomas are removed or not, the woman should have regular check-ups so that her doctor can check for changes.