The words soft tissue confuse many people. Soft tissues are what hold the body together. They include muscles, tendons, blood vessels, fat, nerves, and deep skin tissues. Soft tissues do not include bones or other organs. Although body parts such as lungs, breasts, and colons are soft, they have specific functions. Because they perform very specific "jobs," they are not considered soft tissue.
Sarcoma is cancer. Soft tissue sarcoma is cancer in one of the soft tissues. There are many different kinds of soft tissue sarcoma. In general, soft tissue sarcomas are rare. Many of the soft tissue tumors start in the arms or legs. Most of the others are found in the torso, or trunk area. Less often, they are found in the head and neck or inside other organs, including the liver, lung, kidney, uterus, breast, gastrointestinal tract, or the abdominal cavity.