A fibroadenoma is a common type of benign or noncancerous lump that can develop in the breast. Larger fibroadenomas may feel like a hard or rubbery marble that moves around under the skin.

A person with a fibroadenoma is unlikely to experience any symptoms other than the lump itself. A fibroadenoma is highly unlikely to lead to cancer and rarely causes any complications.

In this article, we look at the causes of fibroadenomas and how doctors diagnose and treat them.

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A fibroadenoma is a benign tumor that can develop in the breast. Doctors do not know why some people develop them while others do not. They are common in females and rare, but possible, in males.

Fibroadenomas consist of glandular and connective tissue, and they can vary in size. Some are so small that a person cannot feel them, while others are easy to locate during a self-examination.

If a fibroadenoma is large enough to feel, it might feel like a round or oval marble within the breast. The lump will usually feel firm or rubbery, and a person will be able to move it under the skin.

A person may have one fibroadenoma or many. Fibroadenomas may maintain their size or grow or shrink over time.

Doctors classify fibroadenomas as either simple or complex. According to the American Cancer Society (ACS), simple fibroadenomas look the same all over when a doctor examines them under a microscope. Complex fibroadenomas are usually larger and have different features.

Doctors do not know exactly what causes fibroadenomas, but they think that estrogen sensitivity may play a role.

Breasts comprise:

  • lobules, which are milk-producing glands
  • ducts, which carry milk to the nipple
  • glandular, fatty, and fibrous tissue

Fibroadenomas develop from a lobule. Ducts and glandular tissue grow over it, forming a solid lump.

A fibroadenoma is not usually painful or tender to the touch. Most people do not experience any symptoms other than the lump.

According to the charity Breast Cancer Now (BCN), fibroadenomas may feel tender before a person’s period. They may also get bigger during pregnancy, when breastfeeding or chestfeeding, or while taking hormone replacement therapy. Fibroadenomas will usually return to their previous size after hormone fluctuations.

The ACS notes that doctors can detect a fibroadenoma through an initial physical examination if it is large enough. If the doctor suspects a fibroadenoma, they will confirm it using an imaging test, such as a mammogram, an ultrasound, or both.

The doctor may recommend a biopsy to ensure that the lump is a fibroadenoma. The individual will receive a local anesthetic, after which the doctor will remove a small sample of the lump to send to a laboratory for testing.

Doctors may recommend the following treatments for fibroadenoma:


If a fibroadenoma has any abnormalities, a doctor may recommend surgical removal. In lumpectomy surgery, also called excision biopsy, a doctor will make a small cut in the breast to remove the fibroadenoma.

This procedure can take place under either a local or general anesthetic. The choice will depend on the features of the fibroadenoma and its location in the breast.

According to 2015 research, surgery is rarely necessary if the cells of the fibroadenoma appear normal. Surgery could leave scars on the breast, which may interfere with future imaging tests.

The American Board of Internal Medicine recommends that doctors do not surgically remove fibroadenomas that are smaller than 2 centimeters. If they are increasing in size or bothersome to a person, doctors might recommend surgery.

Vacuum-assisted excision biopsy (VAB)

A VAB is a nonsurgical procedure to remove a fibroadenoma. A doctor will inject a local anesthetic before making a small cut into the skin. They will then insert a probe that connects to a vacuum device that sucks out the fibroadenoma.

A doctor will then send the fibroadenoma tissue for testing at a laboratory. People may experience some pain or bruise in the area after a VAB. In some cases, people may have a small dent in the breast from the tissue removal.


Cryoablation is another nonsurgical option for fibroadenoma removal. Cryoablation uses liquid nitrogen to freeze and destroy unwanted tissue in the body. Once the cells of the fibroadenoma die, the immune system’s white blood cells clear the dead tissue from the body.

A doctor may use imaging techniques, such as an ultrasound or a CT scan, to help them locate the area to target with cryoablation. They can then insert a probe through a small cut in the skin to reach a fibroadenoma and apply the liquid nitrogen.

Fibroadenomas do not usually cause any complications. It is possible that a person may develop breast cancer out of a fibroadenoma, but this is highly unlikely. The risk of breast cancer may be slightly higher with complex fibroadenomas than with simple fibroadenomas.

Fibroadenomas are noncancerous and do not usually cause significant problems. They tend to shrink after menopause.

Fibroadenomas can also change size in line with hormone fluctuations before menopause. A doctor may suggest regular checkups to monitor these changes if this occurs.

A person should talk with a doctor if they notice any changes in the breasts, regardless of how long after a diagnosis of fibroadenoma these occur.

In most cases, a fibroadenoma will stay the same or shrink, not affecting a person’s life. People may not experience any symptoms other than a lump, but some individuals may feel pain or tenderness.

Most people with a fibroadenoma will not need surgery to remove it. However, a doctor may recommend nonsurgical treatment, which involves a VAB or cryoablation.

It is highly unlikely that fibroadenoma will lead to breast cancer or cause other significant issues.

However, it is essential that anyone who finds a lump in their breast seeks further medical advice. Identifying a fibroadenoma is straightforward, and a diagnosis can give a person peace of mind and rule out other conditions.

Read this article in Spanish.