Leiomyosarcoma is a soft tissue sarcoma that attacks smooth muscle cells, usually in the gastrointestinal tract, retroperitoneum, and uterus. Extremely rare, only about 1 to 2 percent of all solid tumors are soft tissue sarcomas, and only a small percentage of those tumors are described as leiomyosarcomas.

Due to the elasticity of the tissue that leiomyosarcomas form in, the tumors often grow to significant sizes before any symptoms become apparent. The most common signs of the disease when any occur are bleeding and the low hemoglobin levels associated with substantial loss of blood. Occasionally there will be pain associated with the mass pushing against nerves or muscular tissue, and only rarely is a leiomyosarcoma palpable.

The cause of leiomyosarcoma is not yet fully understood, but a number of risk factors for the disease have been identified. One of the most notable of these factors is age, the vast majority of leiomyosarcoma tumors occurring in individuals that are more than 50 years old. In children, the disease is extremely rare. Heredity also appears to be involved in the development of leiomyosarcoma, individuals with various inherited diseases, such as neurofibromatosis, displaying an increased incidence.

The size and grade of leiomyosarcoma tumors are the primary determinants of prognosis, which is typically poor since the cancer is very difficult to detect until it is in an advanced state and begins to produce symptoms. In fact, studies indicate that nearly 40 percent of the tumors are discovered incidentally during unrelated testing or other procedures rather than from complaints of the patient that could be connected to the cancer. By the time that leiomyosarcoma is diagnosed, often the cancer has metastasized. Unlike other soft tissue sarcomas, this metastasis usually affects the liver and the peritoneum first, instead of the lungs.

Leiomyosarcoma at 10x Magnification - Evidence suggests that exposure to certain chemical substances increases the risk of developing leiomyosarcoma. Some of the chemicals in question include various wood preservatives, industrial pollutants, and pesticides.

Leiomyosarcoma at 20x Magnification - The treatment for leiomyosarcoma most commonly involves surgery, but radiation therapy and chemotherapy are also sometimes utilized, though they are ineffective against certain types of the disease, especially the type that involves tumor formation in the gastrointestinal tract.