A breast lump is a growth of tissue that develops within your breast. Different types of breast lumps can vary in the way they look and feel.

You might notice:

• A distinct lump with definite borders
• A firm, hard area within your breast
• A thickened, slightly more prominent area in your breast that's different from surrounding breast tissue
• Other breast changes, such as redness, dimpling or pitting of the skin
• One breast that's noticeably larger than the other
• Nipple changes, such as a nipple that's pulled inward or spontaneous fluid discharge from your nipple
• Persistent breast pain or tenderness, which might increase during your menstrual period

Sometimes, a breast lump is a sign of breast cancer. That's why you should seek prompt medical evaluation. Fortunately, however, most breast lumps result from noncancerous (benign) conditions.

Breast lumps can be caused by:

• Breast cancer
• Breast cysts (fluid-filled sacs in breast tissue that are usually benign)
• Fibroadenoma (a solid, benign mass most common in young women)
• Fibrocystic breasts (lumpy or rope-like breast tissue)
• Galactocele (a milk-filled cyst that's usually harmless)
• Injury or trauma to the breast
• Intraductal papilloma (a benign, wartlike growth in a milk duct)
• Lipoma (a slow-growing, doughy mass that's usually harmless)
• Mastitis (an infection in breast tissue that most commonly affects women who are breast-feeding)

Make an appointment to have a breast lump evaluated, especially if:

• The lump feels firm or fixed
• The lump doesn't go away after four to six weeks
• You notice skin changes on your breast, such as redness, crusting, dimpling or puckering
• You have discharge, possibly bloody, from your nipple
• Your nipple is turned inward and isn't normally positioned that way
• You can feel a lump in your armpit and it seems to be getting bigger