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.
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Fibroadenomas are solid breast lumps that usually are:
- Round with distinct, smooth borders
- Easily moved
- Firm or rubbery
You can have one or many fibroadenomas in one or both breasts.
When to see a doctor
In healthy women, normal breast tissue often feels lumpy. Make an appointment with your doctor if:
- You detect a new breast lump
- You notice other changes in your breasts
- A breast lump you've had checked before has grown or otherwise changed and appears to be separate from the surrounding breast tissue
The cause of fibroadenomas is unknown, but they might be related to reproductive hormones. Fibroadenomas occur more often during your reproductive years, can become bigger during pregnancy or with use of hormone therapy, and might shrink after menopause, when hormone levels decrease.
Types of fibroadenomas
In addition to simple fibroadenomas, there are:
- Complex fibroadenomas. These can contain changes, such as an overgrowth of cells (hyperplasia) that can grow rapidly. A pathologist makes the diagnosis of a complex fibroadenoma after reviewing the tissue from a biopsy.
- Juvenile fibroadenomas. This is the most common type of breast lump found in girls and adolescents between the ages of 10 and 18. These fibroadenomas can grow large, but most shrink over time, and some disappear.
- Giant fibroadenomas. These can grow to larger than 2 inches (5 centimeters). They might need to be removed because they can press on or replace other breast tissue.
- Phyllodes tumor. Although usually benign, some phyllodes tumors can become cancerous (malignant). Doctors usually recommend that these be removed.
Most fibroadenomas don't affect your risk of breast cancer. However, your breast cancer risk might increase slightly if you have a complex fibroadenoma or a phyllodes tumor.