A fibroadenoma (fy-broe-ad-uh-NO-muh) is a solid breast lump. This breast lump is not cancer. A fibroadenoma happens most often between ages 15 and 35. But it can be found at any age in anyone who has periods.

A fibroadenoma often causes no pain. It can feel firm, smooth and rubbery. It has a round shape. It might feel like a pea in the breast. Or it may feel flat like a coin. When touched, it moves easily within the breast tissue.

Fibroadenomas are common breast lumps. If you have a fibroadenoma, your health care provider may tell you to watch for changes in its size or feel. You may need a biopsy to check the lump or surgery to remove it. Many fibroadenomas need no further treatment.


A fibroadenoma is a solid breast lump that often causes no pain. It is:

  • Round with distinct, smooth borders
  • Easily moved
  • Firm or rubbery

A fibroadenoma often grows slowly. The average size is about 1 inch (2.5 centimeters). A fibroadenoma can get bigger over time. It may be tender or cause soreness a few days before your period. A large fibroadenoma may hurt when you touch it. But most often, this type of breast lump causes no pain.

You can have a single fibroadenoma or more than one fibroadenoma. They can occur in one or both breasts.

Some fibroadenomas shrink over time. Most fibroadenomas in adolescents shrink over many months to a few years. They then disappear. Fibroadenomas may also change shape over time.

Fibroadenomas may get bigger during pregnancy. They might shrink after menopause.

When to see a doctor

Healthy breast tissue often feels lumpy. Make an appointment with your health care provider if you:

  • Find a new breast lump
  • Notice other changes in your breasts
  • Find that a breast lump you had checked in the past has grown or changed in any way

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The cause of fibroadenomas is not known. They might be related to hormones that control your periods.

Less common types of fibroadenomas and related breast lumps may not act the same as typical fibroadenomas. These types of breast lumps include:

  • Complex fibroadenomas. These are fibroadenomas that can get bigger over time. They can press on or displace nearby breast tissue.
  • Giant fibroadenomas. Giant fibroadenomas grow quickly to larger than 2 inches (5 centimeters). They also can press on nearby breast tissue or push it out of place.
  • Phyllodes tumors. Phyllodes tumors and fibroadenomas are made of similar tissues. But under a microscope, phyllodes tumors look different from fibroadenomas. Phyllodes tumors typically have features associated with growing faster. Most phyllodes tumors are benign. This means they are not cancer. But some phyllodes tumors may be cancer. Or they could become cancer. Phyllodes tumors often cause no pain.


Common fibroadenomas do not affect your risk of breast cancer. But your risk might go up a bit if you have a complex fibroadenoma or a phyllodes tumor.

Oct. 13, 2022
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