A type of cancer that forms in fibrous (connective) tissue. It can occur anywhere in the body. Adult-type fibrosarcoma may spread to nearby tissue or to other parts of the body, such as the lungs or bones. It may also recur (come back) after treatment. Adult-type fibrosarcoma usually occurs in young and middle-aged adults, but it can also occur in children. It is a type of soft tissue sarcoma.