After Treatment Further Info Background Inside the breasts are glands that produce and release milk after a woman has a baby. The glands that make the milk are called lobules and the tubes that connect them to the nipple are called ducts. There are several types of breast tumors. These lumps are often caused by fibrocystic changes. Cysts are fluid-filled sacs, and fibrosis refers to connective tissue or scar tissue formation.
Fibrocystic changes can cause breast swelling and pain.
The breasts may feel lumpy and sometimes there is a clear or slightly cloudy nipple discharge. Benign breast tumors are abnormal growths, but they do not spread outside of the breast and they are not life-threatening. How it spreads When breast cancer spreads outside the breast, cancer cells often are found in the lymph nodes under the arm. Cancer cells may spread beyond the breast such as to other lymph nodes, the bones, liver, or lungs. When breast cancer spreads, it is called metastatic breast cancer even though it is found in another part of the body.