Synovial sarcoma is a malignant tumor of the soft tissues, usually around joints. Under the microscope the tumor resembles synovial tissue (the lining tissue of joints). Synovial tissue is found around the tendons (bands of fiber that connect muscle to bone) and can form bursa (fluid filled cushioning pouches or sacs found in spaces between tendons, ligaments, and bones) found in the area of joints.
Synovial sarcoma tends to occur in adolescents and young adults, and it affects more males than females; the most common location is the thigh near the knee, but synovial sarcoma can also occur near other joints, mainly in the arms and legs — it seldom arises within a joint. Synovial sarcoma can spread to other areas of the body, particularly to involve regional lymph nodes. Spreading to distant body tissues occurs in about half of all cases, usually months to years after the initial diagnosis is made, although they are at times present at diagnosis.
Synovial sarcoma is a rare tumor. It is one of many types of cancer classified as a soft tissue sarcoma, cancer that originates in soft tissue, which includes fat, muscles, tendons, nerves, synovial tissue, blood vessels, and other fibrous tissue. As a group, soft tissue sarcomas account for less than 1 percent of all new cancer cases each year. In the United States, approximately 900 children and adolescent.
