A breast lump is a localized swelling, protuberance, bulge, or bump in the breast that feels different from the breast tissue around it or the breast tissue in the same area of the other breast.
There are different reasons why breast lumps develop. Most lumps are not cancerous and do not pose any risk. Causes include infection, trauma, fibroadenoma, cyst, fat necrosis, or fibrocystic breasts. Breast lumps may develop in both males and females, but they are much more common in females.
The female breast consists of different types of tissue. The two main types are milk glands, where milk is made, and milk ducts, or tubes, for milk to pass through to reach the nipple. Breast tissue composition can vary, depending on the function. For example, when a woman is breastfeeding, her breasts will change. They will feel and look different.
The breast also contains fibrous connective tissue, fatty tissue, nerves, blood vessels, and lymph nodes. Each part of the breast can react in different ways to changes in body chemistry. These changes impact the sensations and texture of the breast, and they can affect the development of breast lumps.
A breast cyst is a localised collection of fluid in the breast. Fluid is constantly being produced and reabsorbed in the milk ducts in the breast. When a duct becomes blocked, or the amount of fluid produced is greater than the amount absorbed, fluid accumulates which causes cysts. Cysts can be single or multiple. They can come and go, and vary in size during the menstrual cycle. Breast cysts are very common. Studies have reported cysts in up to 50% of women who attend breast clinics. Cysts can develop in women of any age. They are most common in the 30–50 year age group. They usually disappear after menopause, but in some women they can last throughout life. Cysts are more common in post-menopausal women who take hormone replacement therapy than in post-menopausal women who do not. All of these factors support the theory that breast cysts are hormonally responsive, although it is not clear why some women form cysts and others do not.
Fibrocystic breasts are characterized by lumpiness and usually discomfort in one or both breasts. The lumpiness is due to small breast masses or breast cysts. The condition is very common and benign, meaning that fibrocystic breasts are not malignant (cancerous). Fibrocystic breast disease (FBD) is now referred to as fibrocystic changes or fibrocystic breast condition, is the most common cause of “lumpy breasts” and affects more than 60% of women. The condition primarily affects women between the ages of 30 and 50, and tends to resolve after menopause.
The diagnosis of fibrocystic breasts is complicated by the fact that the condition can vary widely in its severity.