Breast cancer develops when normal cells within breast tissue undergo changes that lead to their uncontrolled growth and proliferation. Many different types of breast tumors exist and can originate from different cell types within breast tissue. While the majority of breast tumors originate from cells of the the milk ducts or the milk-producing lobules of the breast, other equally dangerous tumor types can develop from other cells and tissues of the breast.
Invasive Breast Tumors
Invasive breast tumors originate from cells of the milk duct or the milk-producing lobules of the breast. These tumors start off as microscopic "in situ" tumors that are not detectable by manual exam and are usually only seen using mammography. As microscopic in situ tumors grow, they invade other tissues of the breast to become "invasive" tumors, which can be felt as a small lump or solid mass in the breast. The American Cancer Society and the Mayo Clinic explain that about 90 percent of all breast tumor types are invasive tumors that originate from ductal cells and are referred to as "invasive ductal carcinomas." Invasive tumors are removed by surgery, or biopsied and analyzed for specific tumor markers to determine more specific details about tumor type.
Triple-Negative Breast Tumors
Triple-negative breast tumors lack three major markers common to many breast tumors. These markers are estrogen receptor, progesterone receptor and the tumor marker HER2. As triple-negative tumors lack the receptors that are targeted by common breast cancer drugs, the treatment of triple-negative tumors requires different chemotherapy strategies. According to the American Cancer Society, triple-negative tumors are more likely to occur in younger women and African Americans.
Angiosarcoma
Angiosarcomas develop from cells that line the blood vessels of the breast tissue. The American Cancer Society explains that this type of cancer is very rare. Angiosarcomas often result from radiation treatments of previous tumors and can appear as late as five to ten years post-radiation treatment. Angiosarcomas are very aggressive and are treated with a course of radiation and chemotherapy used to similarly treat other types of sarcomas.
Adenoid Cystic Carcinoma
Adenoid cystic carcinomas, also known as adenocystic carcinomas, have features of a glandular tumor and appear cylindrical when examined under a microscope. According to the American Cancer Society, these tumors are usually confined to breast tissue and rarely invade the lymph nodes. This lack of metastasis by adenocystic carcinomas makes them very treatable and gives patients with this type of tumor a good prognosis.
Inflammatory Breast Cancer
The National Cancer Institute describes this rare form of breast cancer as having symptoms similar to a breast infection. Inflammatory breast cancer makes the breast feel warm and causes the skin of the breast to look red and pitted like the skin of an orange. The breast may also become larger and start to itch. These changes come about as cancer cells block the lymph vessels of the breast. This type of cancer is hard to identify by mammogram as there is no characteristic lump or mass like that of the invasive breast cancers. This type of cancer is typically diagnosed through a biopsy and treated with surgery, chemotherapy, radiation and hormone therapies.
