Cancer is a term used to describe a group of diseases characterized by out of control cell growth and division. Out of control cell growth results in a lump or mass known as a tumor. Cancerous tumors are referred to as malignant and can be life threatening. Cells from the tumor can break away and spread to other parts of the body. Most cancers are named for the part of the body in which they originate.
Breast cancer is a form of cancer that begins in the breast tissue.
There are several types of breast tumors. Fibrocystic changes can cause breast swelling and pain, and the breasts may feel lumpy and there might be a clear or cloudy nipple discharge. Benign breast tumors are abnormal growths, but they do not spread and are not life-threatening. In situ refers to a tumor that has not spread.