Breast cancer is the result of cells in the breast developing genetic abnormalities, which causes them to grow abnormally quickly and spread to other tissues. Not all kinds of breast cancer are the same, however; the prognosis for aggressively spreading cancers is much worse than for the other types.
Inflammatory Breast Cancer
Inflammatory breast cancer, as BreastCancer.org explains, is a fairly rare form of breast cancer (between 1 percent and 5 percent of all cases of breast cancer are of this variety). Inflammatory breast cancer is a very aggressive form of breast cancer that can rapidly spread throughout the body. Instead of forming a distinct lump, inflammatory breast cancer usually causes a generalized swelling and reddening of the breast. The symptoms of this kind of breast cancer can rapidly worsen over a matter of days, and it should be treated immediately. This kind of cancer may not be detected by a mammogram.
Triple Negative Breast Cancer
According to the American Cancer Society, triple negative breast cancer describes breast cancers that have unusual cellular characteristics. Triple negative breast cancer cells do not have the machinery to respond the hormones estrogen and progesterone, nor do they have unusually high levels of a protein called HER2 (a protein that's commonly elevated in breast cancer cells). Because many breast cancer treatments utilize estrogen and progesterone receptors or target the HER2 protein, this form of breast cancer can be very difficult to treat. It also tends to be more aggressive than some other forms of breast cancer.
Invasive Lobular Carcinoma
Invasive lobular carcinoma describes an aggressive form of breast cancer that begins in the parts of the breast that produce milk (the lobules). Invasive lobular carcinoma is able to spread from the breast to other parts of the body, which is also known as metastasis. Invasive lobular carcinomas can be difficult to detect using a mammogram, which makes them harder to diagnose early.
Paget's Disease of the Nipple
Paget's disease of the nipple is a form of breast cancer in which the cancer cells collect around the patient's nipple. It can lead to the areola and the nipple becoming red, itchy and scaly. BreastCancer.org explains that scientists don't actually understand how this form of breast cancer develops. It's a serious type of breast cancer, because patients with this form of breast cancer often have breast cancer elsewhere in their breast as well.
