A firm, round, noncancerous growth in the breast tissue

  • Most common between the ages of 15 and 30
  • More common in black women
  • Lifestyle is not a significant factor

A fibroadenoma is an overgrowth of a breast lobule (the part of the breast that produces milk) and surrounding connective tissue. Although the cause of this condition is not fully understood, the development of a fibroadenoma is thought to be linked to the sensitivity of breast tissue to female sex hormones. The lumps tend to grow more quickly during pregnancy, probably because of the increased levels of female sex hormones. Fibroadenomas appear more commonly in women aged between 15 and 30 and in black women.

A fibroadenoma is usually painless. These lumps can develop in any part of the breast and can be up to about 6 cm (2 1 / 2 in) in size. There may be more than one lump and sometimes both breasts are affected. In some women, multiple fibroadenomas develop together with a generalized thickening of the breast tissue.

It is important to become familiar with your breasts so that you can recognize any abnormal changes (see Breast awareness). Fibroadenomas are harmless but you must consult your doctor promptly if you detect any new lump so that the possibility of breast cancer can be investigated.

What might be done?

Your doctor will probably give you a physical examination and refer you to a breast clinic. At the clinic you will usually undergo triple assessment: examination by a doctor; breast imaging by ultrasound scanning and/or mammography; and fine-needle aspiration and/or a core biopsy of the lump. In a fine-needle aspiration, a sample of cells is taken and examined microscopically for cancerous cells. In a core biopsy a sample of tissue is taken and examined for cancerous cells.

Small fibroadenomas do not usually need treatment. About 1 in 3 fibroadenomas become smaller or disappear completely within 2 years. If you are worried about the fibroadenoma, or if it grows larger, surgical removal may be recommended. After removal, the lump will be examined under a microscope for the presence of cancerous cells. In most cases, fibroadenomas do not recur after treatment.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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