What Is Fibroadenoma?

There is nothing good about a breast exam. It’s uncomfortable. Embarrassing. Nine times out of ten the exam room is the temperature of a walk-in cooler. None of that even registers, however, when compared to the moment the doctor pauses and returns to the same area over and over during the examination. Then come the words no one ever wants to hear, “I feel a mass in this breast.” Although not fast enough to stop your life from flashing in front of your eyes, this will quickly be followed by an explanation that it is probably a type of cyst called a fibroadenoma and is unlikely to be cancerous.

Fibroadenomas are the most common type of benign, meaning non-cancerous, tumor. Unless so small that they can only be detected through a mammogram or other test, when the breast is palpated, they feel like round, solid lumps that move freely within the breast. Because fibroadenomas often occur during pregnancy or with the use of hormone therapy and shrink when hormone levels decrease, they may be related to reproductive hormones, but that has not been proven.

Types of Fibroadenomas

There are several different classifications of fibroadenomas, including:

  • Simple fibroadenomas – these are the most common and, when examined under a microscope, look the same through and through.
  • Complex fibroadenomas – determined by reviewing tissue from a biopsy, complex fibroadenomas contain one of the following features: sclerosing adenosis, papillary apocrine hyperplasia, cystic change or epithelial calcification.
  • Juvenile fibroadenomas – found in girls between the ages of 10 and 18, these can grow relatively large, but most shrink over time and some totally disappear.
  • Giant fibroadenomas – differing from other types because of their size, giant fibroadenomas can grow larger than 2 inches (5 centimeters) in diameter. Surgery is not normally recommended for fibroadenomas, but when they grow so large that they press on or replace other breast tissue, they may need to be removed.
  • Phyllodes tumor – similar to fibroadenomas and also usually benign, some phyllodes tumors can become cancerous (malignant) and need to be followed closely by a doctor.

The top question on the mind of everyone diagnosed with any sort of tumor after “Do I have cancer?” is “Does this mean I am more likely to get cancer?” According to the American Cancer Society, “Women with simple fibroadenomas have a slightly increased risk of breast cancer – about 1½ times the risk of women with no breast changes. Complex fibroadenomas seem to increase the risk slightly more than simple fibroadenomas.”


Doctors have differing opinions about whether or not to surgically remove fibroadenomas. If the mass is small, the recommendation will likely be to wait and see whether it shrinks on its own, stays the same or grows. This is especially true during and following pregnancy and breast feeding. There is a good chance that once hormone levels drop back to normal, the lump will disappear, according to many a website.

If there is any doubt in your doctor’s mind about the lump or if it does get larger, there will probably be the decision to advise removal. This will confirm that there is no evidence of cancer. Plus, a large growth can distort the shape of the breast and affect surrounding tissue.

Whatever decisions are made about treatment, follow-up is extremely important. Awareness, self-exams and screening have made a huge difference in breast cancer survivorship. It may be a fibroadenoma today, but that may not be the case tomorrow.

If you would like to learn more about this subject, please check out the video embedded below.