In general, sarcomas that are not classified as osteosarcoma, Ewing's sarcoma, or rhabdomyosarcoma are extremely rare in children and young adults. These include:
- alveolar soft part sarcoma (ASPS) -- found in saclike cavities such as those in the lungs
- desmoplastic small round cell tumor (DSRCT) -- typically found in the abdomen
- fibrosarcoma and dermatofibroma -- found in the soft tissues
- gastrointestinal stromal tumors (GIST) -- typically found in the abdomen
- infantile hemangiopericytoma -- found in connective tissue surrounding capillaries
- leiomyosarcoma -- found in smooth muscles
- liposarcoma -- found in the soft tissues
- spindle cell sarcomas and malignant fibrous histiocytoma (MFH) -- found in different areas of the body, typically bone and muscle
- synovial sarcoma -- found the soft tissues most often around the knee
Treatment of these soft tissue sarcomas are individualized and can include a combination of systemic chemotherapy, surgery, and radiation therapy.