There are many causes for lumps in the breast. These range from normal changes in your body to abnormal breast disease. Breast lumps are either benign (noncancerous) or malignant (cancerous).

See also: Breast lumps and cancer

Some lumps are age-dependent. Newborn boys and girls both have lumps of enlarged breast tissue beneath the nipple, which have been stimulated by the mother's hormones. These disappear within a few months of birth.

Beginning as early as age 8, girls may develop tender lumps beneath one or both nipples (frequently only one). These lumps are breast buds and are one of the earlier signs of the beginning of puberty.

Boys at mid-puberty (usually around age 14 or 15) may develop tender lumps beneath one or both nipples, also in response to the hormonal changes of puberty. These tend to disappear over a period of 6 months to 1 year. See: Gynecomastia

It is also important to remember that hormonal changes just prior to menstruation may give a lumpy or granular feeling to the breast tissue.

The discovery of a lump in the breast usually brings the thought of breast cancer immediately to mind. Breast cancer may occur in men and women, but it is much more common in women. For specific information, see the article on breast cancer.

However, it is important to remember that 80-85% of all breast lumps are benign, especially in women under age 40. Benign causes of breast lumps include:

• Breast infection (breast abscess)
• Fibrocystic breast disease
• Fibroadenoma
• Fat necrosis (damage to some of the fat tissue within the breast; a fat necrosis mass cannot be distinguished from breast cancer without biopsy)