A bloody discharge may be caused by a noncancerous breast tumor (such as a tumor
in a
milk duct, called an intraductal papilloma) or, less commonly, by
breast cancer. Among women who have an abnormal discharge, breast cancer is the cause in fewer than 10%. A greenish discharge is usually due to a fibroadenoma, a noncancerous solid lump. A discharge that contains pus and smells foul may result from a breast infection.