Types of Breast Cancer

Breast cancer is classified into two types, based on whether or not it is invasive: 

  • Non-invasive (in situ) breast cancer: Cancer cells have not spread to adjacent areas of your breast—they have remained in their place of origin. The most common type is ductal carcinoma in situ (DCIS), which occurs in the lining of the milk ducts. Noninvasive breast cancer is sometimes called "stage 0" cancer.
  • Invasive breast cancer: Cancer cells infiltrate or spread outside the membrane that lines a duct or lobule, into surrounding tissues. The cancer cells can then travel to other parts of your body. Invasive breast cancer can be stage I, II, III, or IV, depending on how advanced it is.

Breast cancer can be further classified according to what type of tissue it arises from

Milk ducts: Ductal carcinoma is the most common type of breast cancer.

Milk-producing lobules: Lobular carcinoma originates in the lobules, where breast milk is produced.

Connective tissues (muscles, fat and blood vessels): Rarely, breast cancer can originate from these breast tissues; in this case, it's called sarcoma.

Inflammatory Breast Cancer: The Rarest and Most Aggressive Form

  • Inflammatory breast cancer (IBC) is a rare form of breast cancer of sudden onset (weeks to months) and can easily be confused with a breast infection (mastitis).
  • The affected breast is red, swollen, warm and tender because cancer cells have blocked the lymphatic vessels in your breast.
  • You might or might not have a lump.
  • IBC accounts for between 1 and 5 percent of all breast cancer cases in the U.S., and is more common among younger women and African American women.
  • There have been some cases documented in men. IBC is the most aggressive form of breast cancer, and survival rates are worse than for other types of breast cancer.
  • You should seek medical attention immediately if you have the above symptoms—or if you are being treated for mastitis but your symptoms are not resolving as expected.

Signs and Symptoms to Watch For

The most common signs and symptoms of breast cancer include the following:

  • A breast lump or thickening that feels different from the surrounding tissue
  • Bloody discharge, or other unusual discharge, from your nipple
  • A change in your breast's size or shape
  • Changes in the skin on your breast, such as dimpling or indentation
  • Redness or pitting of your breast skin—kind of like the skin of an orange
  • Pain or tenderness in your breast
  • An inverted nipple
  • Peeling or flaking of the nipple
  • Enlarged lymph nodes or swelling in your armpit

If you have any of these changes, you should consult your healthcare provider immediately. But don't panic—remember, the majority of breast tumors are benign. Many of the above signs can indicate other issues besides cancer, and your healthcare provider can help you sort it out.