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Fibroadenoma of Breast
A fibroadenoma is a benign (noncancerous) tumor. We'll teach you everything you need to know, from how it feels to how it's treated.

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What Is a Fibroadenoma?

Finding a lump in your breast can be a scary experience, but not all lumps and tumors are cancerous. One type of benign (non-cancerous) tumor is called a fibroadenoma. While not life-threatening, a fibroadenoma may still require treatment. 

A fibroadenoma is a non-cancerous tumor in the breast that is commonly found in women under the age of 30. According to Mammotome, fibroadenomas are diagnosed in approximately 10 percent of women in the United States (Mammotome). African-American women are more likely to develop these tumors.

The tumor consists of breast tissue and connective (stromal) tissue. According to Dr. David Zieve for PubMed, while most women only have one tumor, 10 to 15 percent of women have multiple lumps (PubMed). Fibroadenomas can occur in one or both breasts.


Some fibroadenomas are so small that they cannot be felt. When you are able to feel one, it is very distinct from the surrounding tissue. The edges are clearly defined and the tumors have a detectable shape. They are moveable under the skin and are typically not tender. These tumors often feel like marbles, but may have a rubbery feel to them.


The exact cause of fibroadenomas is not known. Hormones such as estrogen may play a part in the growth and development of the tumors. Taking oral contraceptives before the age of 20 has been associated with a higher risk of developing fibroadenomas.

These tumors may grow, particularly during pregnancy. During menopause, they often shrink. It is also possible for fibroadenomas to resolve on their own.


There are two types of fibroadenomas: simple fibroadenomas and complex fibroadenomas. The simple tumors do not increase breast cancer risk and look the same all over when viewed under a microscope. The complex tumors contain other components such as macrocysts (fluid-filled sacs large enough to feel and to see without a microscope) and calcifications (calcium deposits).

Complex fibroadenomas can slightly increase your risk of breast cancer. The American Cancer Society states that women with complex fibroadenomas have approximately one and a half to two times greater risk of developing breast cancer than women with no breast lumps (ACS).

How Are Fibroadenomas Diagnosed?

A physical examination will be conducted and your breasts will be palpated (examined manually). A breast ultrasound or mammogram imaging test may also be ordered. A breast ultrasound involves lying on a table while a hand-held device called a transducer is moved over the skin of the breast, creating a picture on a screen. A mammogram is an X-ray of the breast taken while the breast is compressed between two flat surfaces.

A fine needle aspiration or biopsy may be performed to remove tissue for testing. This involves inserting a needle into the breast and removing small pieces of the tumor. The tissue will then be sent to a lab for microscopic examination to determine the type of fibroadenoma and if it is cancerous.

Treating a Fibroadenoma

If you are diagnosed with a fibroadenoma, it does not necessarily have to be removed. Depending on your physical symptoms, family history, and personal concerns, you and your doctor can decide whether to have it removed or not. Fibroadenomas that do not grow and are definitely not cancerous can be closely monitored with clinical breast exams and imaging tests, such as mammograms and ultrasounds. 

The decision to have a fibroadenoma removed typically depends on the following:

  • if it impacts the natural shape of the breast
  • if it causes pain
  • if you are concerned about developing cancer
  • if you have a family history of cancer
  • if you received questionable biopsy results

If a fibroadenoma is removed, it is possible for one or more to grow in its place.

Living with a Fibroadenoma

Due to the slightly increased risk of breast cancer, you should have regular checkups with your doctor and schedule regular mammograms if you have fibroadenomas. You should also make breast self-exams a regular part of your routine. If there are any changes in the size or shape of an existing fibroadenoma, call your doctor right away.

Written by: Jaime Herndon
Edited by:
Medically Reviewed by:
Published: Jul 9, 2012
Published By: Healthline Networks, Inc.
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