A rare, slow-growing type of cancer that usually forms in the deep soft tissues of the legs or trunk (chest and abdomen). The cancer may come back many years after treatment and spread to the lungs and the lining of the wall of the chest cavity. The cancer cells usually have a certain genetic change called a translocation (part of one chromosome switches places with part of another chromosome). Low-grade fibromyxoid sarcoma usually occurs in young and middle-aged adults. It is a type of soft tissue sarcoma.