Fibroadenomas of the Breast: Causes, Symptoms, and Treatment

The term fibroadenoma combines the words “fibroma,” meaning a tumor made up of fibrous tissue, and “adenoma,” a tumor of gland tissue. 

A fibroadenoma typically has a well-defined round or oval shape. It may feel rubbery or like a marble.  It can also be flat, like a coin. A fibroadenoma is typically painless. When you touch it, it’s easy to move around under the skin as opposed to being stuck in one place. 

Over time, a fibroadenoma may grow in size or even shrink and disappear. The average fibroadenoma is anywhere from the size of a marble up to 2.5 centimeters (about an inch) in diameter. 

Fibroadenomas can be categorized by their size and growth. There are four types: 

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  Simple fibroadenomas are the most common type. They tend to be smaller and the cells look the same throughout the tissue.

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  Complex fibroadenomas are more common in people older than 35. They tend to be larger and may have calcifications or cysts in them. 

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  Giant fibroadenomas are bigger than 5 centimeters (about 2 inches). 

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  Juvenile fibroadenomas are rare and develop in children and teens between the ages of 10 and 18. 

Experts aren’t sure what causes fibroadenomas to develop, but believe estrogen plays a role. Breast tissue is known to be sensitive to estrogen.  Fibroadenomas tend to grow during pregnancy, when estrogen levels are higher. They tend to shrink during menopause, when estrogen levels are lower.  There may also be genetic causes. 

Although anyone who has a period can develop a fibroadenoma, they are more likely to develop in people between the ages of 15 and 35. Black people have a slightly higher risk of developing a fibroadenoma.

If you or your doctor feels a breast lump, your doctor first does a physical exam and asks about your medical history.

If you’re younger than 30,  your doctor examines the fibroadenoma with ultrasound. 

If you're older than 35, your doctor uses a mammogram to look at the fibroadenoma. 

No matter your age, your doctor also may do a biopsy to look at the type of cells in the fibroadenoma.

Fibroadenomas usually don’t require treatment. They often go away on their own. Your doctor may recommend monitoring the fibroadenoma for changes for a certain amount of time.

But if the fibroadenoma is large and is painfully pressing on other breast tissue, it’s usually removed.

Fibroadenomas can be removed with surgery or they can be frozen and destroyed in a procedure called cryoablation. Cryoablation is less common than surgery.

Fibroadenomas are most often found in the upper, outer part of the breast.

Most fibroadenomas don’t increase breast cancer risk. Complex fibroadenomas, which are very uncommon, slightly increase your risk of breast cancer compared to someone with no breast lumps.

Often fibroadenomas do not require treatment and will go away on their own. However, some will grow slowly and may begin to cause discomfort.

Yes. You can get more than one fibroadenoma. This is why it’s so important to know how your breasts feel and tell your doctor about any new lumps you find.