ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Inflammatory Breast Cancer. To see other pages, use the menu on the side of your screen. Think of that menu as a roadmap to this full guide.
Inflammatory breast cancer is a rare form of breast cancer. The cancer gets its name because the symptoms include redness, tenderness, swelling, and pain in the breast, all of which are similar to a condition called mastitis. Mastitis is an inflammation of the breast. However, unlike mastitis, inflammatory breast cancer does not improve with antibiotic treatment.
About the breast
The breast is made up of different tissue, ranging from very fatty tissue to very dense tissue. Within this tissue is a network of lobes, which are made up of tiny, tube-like structures called lobules that contain milk glands. Tiny ducts connect the glands, lobules, and lobes, carrying the milk from the lobes to the nipple, located in the middle of the areola, which is the darker area that surrounds the nipple. Blood and lymph vessels also run throughout the breast; blood nourishes the cells, and the lymph system drains bodily waste products. The lymph vessels connect to lymph nodes, the tiny, bean-shaped organs that help fight infection.
About inflammatory breast cancer
Cancer begins when healthy cells in the breast change and grow uncontrollably, forming a mass or sheet of cells called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread. Breast cancer spreads when the cancer grows into other parts of the body or when breast cancer cells move to other parts of the body through the blood vessels and/or lymph vessels. This is called metastasis.
In inflammatory breast cancer, the cancer cells block the lymph vessels within the breast, which causes fluid backup and swelling of the breast and overlying skin. Because this type of breast cancer can grow quickly, it is treated with a combination of surgery, radiation therapy, and chemotherapy; see Treatment Options  for more information.
Breast cancer subtypes
Breast cancer is not all one disease, but made up of 3 main subtypes. Special receptors on the outside of the cancer cell help determine the subtype of breast cancer:
Hormone receptor positive. Breast cancers expressing estrogen receptors (ER) and progesterone receptors (PR) are called hormone receptor positive. These cancers may depend on the hormones estrogen and/or progesterone to grow.
HER2 positive. About 20% to 25% of breast cancers depend on the gene called human epidermal growth factor receptor 2 (HER2) to grow. These cancers are called HER2 positive and have excessive numbers of HER2 receptors or copies of the HER2 gene. The HER2 gene makes a protein that is found on the cancer cell and is important for tumor cell growth.
Triple negative. If a person’s tumor does not express ER, PR, and/or HER2, the tumor is called triple-negative. This type of breast cancer may grow more quickly than hormone receptor-positive disease, and may be more sensitive to chemotherapy. Inflammatory breast cancers are often triple negative.
Looking for More of an Overview?
If you would like additional introductory information about breast cancer, explore these related items. Please note these links will take you to other sections on Cancer.Net:
ASCO Answers Fact Sheet : Read a one-page fact sheet (available as a PDF) that offers an easy-to-print introduction to breast cancer.
ASCO Answers Guide : This 52-page booklet (available as a PDF) helps newly diagnosed patients better understand their disease and treatment options, as well as keep track of the specifics of their individual cancer care plan.
Cancer.Net Patient Education Video : View a short video led by an ASCO expert in breast cancer that provides basic information and areas of research.
The next section in this guide is Statistics  and it helps explain how many people are diagnosed with this disease and general survival rates. Or, use the menu on the side of your screen to choose another section to continue reading this guide.