Leiomyosarcoma cancer is a tumor that occurs in smooth muscle cells, according to WebMD. it can form anywhere in the body where there are smooth muscles, including the pancreas, heart, liver and digestive tract. The most common place physicians find leiomyosarcoma is the uterus.
Soft muscles are also called involuntary muscles, WebMD reports. These are muscles that aren't controlled consciously. They include the heart, the digestive tract, the saliva glands and even the muscles that create goose bumps on the skin.
Leiomyosarcoma is part of a family of cancers called soft-tissue sarcomas, WebMD explains. Sarcomas are cancerous tumors that grow in connective tissue such as fat, muscles, nerves, tendons and blood vessels. Soft tissues support and surround other parts of the body.
Although leiomyosarcoma is rare, it is a very aggressive form of cancer, according to the LeioMyoSarcoma Direct Research Foundation. Many oncologists see only one or two cases in their entire careers.
Researchers don't know exactly what causes leiomyosarcoma, but studies have linked both genetic and environmental factors, the LeioMyoSarcoma Direct Research Foundation states. Individuals who inherit particular medical conditions may be more at risk for leiomyosarcoma. Exposure to high levels of radiation, such as that given during radiation therapy used for cancer treatment, may put patients at greater risk.