Fibroadenomas

Fibroadenomas are breast lumps composed of fibrous and glandular tissue. They are the most common of benign breast tumors and, unless considered "complex," meaning they contain cysts, enlarged lobules or small bits of calcium, do not increase the risk of getting breast cancer. Often discovered when a woman does a breast self-exam, fibroadenomas are usually painless, and may not need treatment because they sometimes shrink or disappear on their own.

Risk Factors for Fibroadenomas

It is unknown what causes fibroadenomas. It is believed, however, that their development is related to reproductive hormones, primarily because fibroadenomas appear during a woman's reproductive years; may increase in size during pregnancy or estrogen therapy; and tend to shrink after menopause, when estrogen levels decrease. Other risk factors for fibroadenomas may include:

  • Being between the ages of 15 and 30
  • Being African-American
  • Being pregnant
  • Having no or few full-term pregnancies

Characteristics of Fibroadenomas

The average size of a fibroadenoma is about an inch; anything larger than two inches is referred to as "giant." Approximately 10 to 15 percent of women have several fibroadenomas, often in both breasts. Characteristics of fibroadenomas of any size may include their being:

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

Diagnosis of Fibroadenomas

The first step in diagnosing whether a breast lump is a fibroadenoma is getting a clinical exam from a doctor. Based upon that examination, one or more of the following tests may be recommended:

  • Mammogram
  • Ultrasound exam
  • Fine-needle aspiration
  • Core needle biopsy

If the lump found is a solid mass, it is more likely to be a fibroadenoma, whereas if it is fluid-filled, it is more likely a cyst, which often can be drained. A core needle biopsy, in which tissue from the lump is obtained and sent for analysis, is the definitive way to diagnose that a fibroadenoma is just that, and not a malignant tumor.

Treatment of Fibroadenomas

Many fibroadenomas are left alone and monitored by the patient and her doctor to see if they grow. Growth rates of less than 16 percent per month in women younger than 50, and of less than 13 percent per month in women older than 50, are considered safe.

If a fibroadenoma is large, painful or growing, or a biopsy shows atypical cells, it may be surgically removed via lumpectomy. Newer treatments include laser ablation, which uses heat to destroy the fibroadenoma, and cryoablation, which uses cold. These types of treatment, which can be performed in a doctor's office, leave only small scars and have fast recovery times. Certain criteria, including a fewer-than-four-centimeters lump, must be met for a patient to be eligible for these types of treatment.

Additional Resources