Definition

Leiomyosarcoma is cancer that consists of smooth muscle cells and small cell sarcoma tumor. The cancer begins in smooth muscle cells that grow uncontrollably and form tumors.

Description

Leiomyosarcomas can start in any organ that contains smooth muscle, but can be found in the walls of the stomach, large and small intestines, esophagus, uterus, or deep within the abdomen (retroperitoneal). But for perspective, smooth muscle cancers are quite rare: Less than 1% of all cancers are leiomyosarcomas. Very rarely, leiomyosarcomas begin in blood vessels or in the skin.

Most leiomyosarcomas are in the stomach. The second most common site is the small bowel, followed by the colon, rectum, and...