The breasts undergo periods of tightly regulated growth and development throughout puberty and pregnancy. When cells within the breast become mutated, leading to dysregulation of cell growth, this causes uncontrolled cell proliferation, and breast cancer can develop. There are a number of types of breast cancer tumors, which differ in the originating cell type within the breast, the appearance of the cells within the tumor and the invasiveness of the cancer.
Invasive Ductal Carcinoma
Invasive ductal carcinoma is the general term for cancer that originates from the ducts of the breast, the tubes that connect the lobules, the tissues which produce the milk, to the nipple. According to Breastcancer.org, around 80 percent of breast cancers are considered invasive ductal carcinomas. Invasive ductal carcinoma can affect both women and men, though it is much more common in women. Breastcancer.org reports that the risk of developing invasive ductal carcinoma increases with age, and that more than two-thirds of women diagnosed with the disease are over age 55. Invasive ductal carcinoma can be detected on a mammogram or by physical examination of the breast, and treatment can involve radiotherapy, chemotherapy or surgical removal of the affected tissue.
Comedocarcinoma
Comedocarcinoma is a type of cancer that affects multiple ducts within the breast. It is an invasive form of cancer that often originates from multiple ducts, and can spread to the lymph nodes and other areas of the body. According to the University of Virginia, it is called a comedocarcinoma because there are regions of cell death in the middle of the growths that can be expelled by putting pressure on the tumor, similar to extracting a comedone, or whitehead.
Comedocarcinoma forms a hard lump within the breast that contains areas of calcification visible in a mammogram. It is considered a highly invasive form of ductal carcinoma that requires aggressive treatment, and can require mastectomy.
Medullary Carcinoma
Medullary carcinoma is a type of cancer, originating from the ducts of the breast, which contains cells with a specific appearance. Most cancer cells retain some characteristics of their original cell type, so many ductal carcinomas contain cells that slightly resemble duct cells, but medullary carcinomas are made up of large cells with a stem cell-like appearance.
According to the American Cancer Society, medullary carcinoma represents about 5 percent of breast cancer cases. It is usually considered less invasive and severe than many other forms of ductal cancer. The cancer also typically has well-defined borders, so patients may be able to opt for breast-conserving surgery instead of a mastectomy. Medullary carcinoma is typically treated by surgical methods, radiotherapy and chemotherapy.
