A fibroadenoma is the most common solid nodule or lump found in the breast. It is not cancer and will not turn into cancer. It is comprised of normal elements found in the breast: tissue ("fibrous") and glandular tissue ("adenoma"). It is not uncommon to have more than one fibroadenoma.
Most fibroadenomas form in the breast while a woman is in her 20s or 30s, sometimes in her 40s. Occasionally, a fibroadenoma can enlarge slightly from year to year under stimulation from a woman's own hormones or from hormone replacement therapy. A fibroadenoma will not disappear by itself, and is not know to be related to any particular diet or medical condition.
A large fibroadenoma, which can be felt in a young patient, is generally removed with surgery because it will only get larger, not smaller. A small fibroadenoma, which has been monitored through mammography for two to three years and cannot be felt, generally needs no particular treatment. When a new fibroadenoma is found, often the use of high-resolution breast ultrasound can establish its diagnosis with better than 98 percent certainty. This requires that an additional step be taken to verify the diagnosis. Because some patients (and their physicians) are uncomfortable with the 2 percent chance that the ultrasound diagnosis is inaccurate, different approaches can be used to establish the diagnosis. Essentially, there are three options to establish the diagnosis, with different advantages and disadvantages:
- Observation every six months for two years
- Needle biopsy (tissue or cells are removed with a hollow needle)
- Surgical biopsy (a surgeon makes a cut or incision in the breast to remove tissue)