Soft tissue sarcoma is a rare type of cancer that begins in the tissues that connect, support, and surround other body structures. This includes muscle, fat, blood vessels, nerves, tendons, and the lining of your joints.

More than 50 subtypes of soft tissue sarcoma exist. Some types are more likely to affect children, while others affect mostly adults. These tumors can be difficult to diagnose because they may be mistaken for many other types of growth.

Soft tissue sarcoma can occur anywhere in your body, but the most common types occur in the arms and legs, and in the abdomen. Surgical removal is the most common treatment, although radiation and chemotherapy also may be recommended — depending on the size, type, location, and aggressiveness of the tumor.