What is a breast fibroadenoma?
Fibroadenomas are the most common benign tumor of the breast, as well as the most common breast tumor in women under age 30. Having a fibroadenoma slightly increases the risk of developing cancer in either breast. About one in 15 women with a history of having a fibroadenoma will develop breast cancer during their lifetime, compared to one in 30 women who do not have any risk factors. Removing the fibroadenoma does not change this risk.

Who is most likely to have a breast fibroadenoma?
Fibroadenomas develop in about 8 to 10 percent of pre-menopausal women. They rarely occur or grow larger in post-menopausal women unless they are using hormone replacement therapy. African-American women tend to develop fibroadenomas more often and at an earlier age than white women. Cyclosporine treatment of renal transplant patients has been associated with the development of fibroadenomas.

What characterizes breast fibroadenoma?
Fibroadenomas are usually detected as a solitary round palpable mass. They can also be detected on screening mammography as a mass or area of calcifications. About 10 to 15 percent of women have multiple fibroadenomas. The tumors are usually firm, moveable, and painless. Most stop growing after they reach two to three centimeters in size and may regress after menopause if hormone replacement therapy is not used. On the other hand, fibroadenomas may grow rapidly during pregnancy, during hormone replacement therapy, or during immunosuppression.

How do the primary care physician and the pathologist make a diagnosis?
Because women younger than age 40 are not ordinarily screened with mammography, fibroadenomas in women of this age group are usually felt by hand during a breast examination. Once a lump is detected, the primary care physician will recommend a mammography, ultrasound, or biopsy to learn more about the breast lump. Mammography and breast ultrasound are both imaging exams that create a picture of the breast for physicians to examine. Most fibroadenomas will be seen as well circumscribed solid masses.

Because breast ultrasound does not use radiation, this test is preferred over mammography if you are younger than age 30 or pregnant.

By performing a biopsy, a physician is able to remove a sample of a mass for the pathologist to examine. A fine needle aspiration biopsy removes individual cells through a thin needle. A large core needle biopsy removes a larger piece of tissue (approximately 1 to 3 mm in width) and this larger biopsy often provides a more specific diagnosis. Needle biopsies can be performed for palpable masses or under image guidance (mammography or ultrasound) for non-palpable masses. In some cases, the entire mass may be removed by an excisional biopsy.

How do doctors determine what surgery or treatment will be necessary?
Your clinician, the radiologist, and the pathologist looking at your specimen all provide important information. Together, using their combined experience and knowledge, they determine treatment options most appropriate for your condition. It’s important to learn as much as you can about these treatment options and to make the decision that’s right for you.

What kinds of treatments are available for breast fibroadenoma?
After examining the biopsy specimen, the pathologist will make a diagnosis. If you have a fibroadenoma, the clinician will recommend to either remove it or to leave it in place. If you choose to not remove the fibroadenoma, you will need to monitor it regularly with clinical breast examinations, mammography, and/or breast ultrasound. If you can feel the fibroadenoma, you are encouraged to do self-exams each month and to report any changes to your physician.

Some women with palpable fibroadenomas will want the mass removed. The standard procedure is surgical excision, often performed under local anesthesia. There are also experimental techniques such as focused ultrasound or laser ablation that may be able to remove fibroadenomas without surgery. Some women may choose to enroll in a trial of one of these newer techniques. Clinical trials for breast fibroadenomas may be found at

For more information, go to (a service of the National Institute of Health and the National Library of Medicine) or (eMedicine, a division of Web MD). Type the keywords breast fibroadenomas into the search box

What kinds of questions should I ask my doctors?
Ask any question you want. There are no questions you should be reluctant to ask. Here are a few to consider:

  • Please describe the type of cancer I have and what treatment options are available.
  • What are the chances for my condition turning into cancer?
  • What treatment options do you recommend? Why do you believe these are the best treatments?
  • What are the pros and cons of these treatment options?
  • What are the side effects?
  • Is your medical team experienced in treating the type of cancer I have?
  • Can you provide me with information about the physicians and others on the medical team?
  • If I want a second opinion, could you provide me with the names of physicians and/or institutions that you would recommend?


Astrocytoma: A tumor type originating in the brain or spinal cord, consisting of star-shaped cells called astrocytes.

Malignant: Cancerous.

Pilocytic: Made up of cells that look like fibers when viewed under a microscope.

Primary Brain Tumor: A tumor that originates in the brain or spinal cord tissue rather than spreading to the brain from another part of the body.

Pathologist: A physician who examines tissues and fluids to diagnose disease to assist in making treatment decisions.




Fibroadenoma  NORMAL

Breast fibroadenoma cells
Normal breast cells
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This information was developed by the College of American Pathologists’ Public Affairs Committee in conjunction with the College’s Cancer Committee and Council on Scientific Affairs. The College is providing this information to help you better understand your health. Ultimately any decisions you make about your health, however, should be between you and your doctor.

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