Metaplastic breast cancer is a very rare form of cancer. Whereas most types of breast cancer involve one type of breast tissue, metaplastic breast cancer first develops in one tissue then the cells change characteristics to resemble cells of another tissue type. Due largely to this characteristic, metaplastic breast cancer is very likely to spread to other parts of the body.
Most cases of breast cancer involve the cancer cells spreading and developing tumors within the main structures that are responsible for the transport of milk. These structures, both the ducts and the lobules, are where the majority of tumors are located, whether they are benign or malignant. In metaplastic breast cancer, the disease begins in the epithelial cells.
The epithelial cells, also known as surface cells, are where most forms of cancer begin. Cancers that start in these cells are called carcinomas; another name for metaplastic breast cancer is metaplastic breast carcinoma. From these surface cells, the cancer begins to spread.
Typically, the cancer can also be found in the squamous or skin cells. Skin is a term that is used to describe an outer covering, whether it is the outer covering of the body or the outer covering of an organ. From here, metaplastic breast cancer can often spread to other parts of the body, including the lymph nodes first of the breast and then other parts of the body. The skin tissues of the lungs are also particularly vulnerable to this type of cancer. Any cancer that spreads to multiple areas of the body is known as invasive cancer, and includes this type.
The majority of cases of breast cancer are tied to the body's production of estrogen, and treatments for these types often interfere with natural hormone production. In the case of metaplastic breast cancer, however, there is no such connection to estrogen, and treatments must be adapted. Symptoms are similar to those of other types of breast cancer, and early detection can greatly impact the prognosis. The earlier it is diagnosed, the less time it will have to spread to other areas of the body.
Physical changes in the breast or underarm area, including new lumps or creases, can be among the visible signs that there is something wrong. There also may be some discharge from the breast, or it may feel warm to the touch and swollen. Tenderness can be one of the signs, but it is not necessarily a symptom exclusive to breast cancer. Mammograms and blood tests are some of the ways in which it is diagnosed, similar to other types of breast cancer in this regard.