Each breast has 15 to 20 sections called lobes. Within each lobe are many smaller lobules. Lobules end in dozens of tiny bulbs that can produce milk. The lobes, lobules and bulbs are all linked by thin tubes called ducts. These ducts lead to the nipple in the center of a dark area of skin called the areola. Cancer can start in any of these areas.
* Ductal carcinoma - NCI says the most common type of breast cancer is ductal carcinoma. It begins in the lining of the ducts.
o Ductal carcinoma in situ (DCIS) - DCIS refers to ductal cancer that has not invaded the surrounding breast tissue. This is early-stage breast cancer, and is sometimes considered pre-cancer, although it can develop into invasive breast cancer if not treated.
o Invasive ductal carcinoma (IDC) - In IDC, cancer started in the ducts, then invaded surrounding tissue and, in some cases, has spread beyond the breasts. IDC is the most common invasive breast cancer.
* Lobular carcinoma - Another type of breast cancer, called lobular carcinoma, arises in the lobules.
o Lobular carcinoma in situ (LCIS) - LCIS refers to lobular cancer that has not invaded the surrounding breast tissue. This is early-stage breast cancer, and is sometimes considered pre-cancer, although it can increase a woman's risk of cancer in either breast.
o Invasive lobular carcinoma (ILC) - In ILC, cancer started in the lobules, then invaded surrounding tissue and, in some cases, has spread beyond the breasts.
There are other types of breast cancer. Inflammatory breast cancer is a rare type of late-stage breast cancer in which the breast looks red and swollen because cancer cells block the lymph vessels in the skin of the breast. Symptoms of inflammatory breast cancer include a sudden increase in breast size, itching, dimpling, thickening of the skin, and the breast may feel warm to the touch. Another less common type of cancer, called Paget's disease of breast, is a slowly growing cancer that starts in the milk ducts of the nipple. Symptoms of Paget's disease of breast include a rash, inflammation, crusting or bleeding, discharge, nipple inversion. These symptoms can also indicate a benign condition, but if you have any unusual symptoms, see your doctor at once.