Soft-tissue sarcomas that are not rhabdomyosarcomas are classifieds as non-rhabdyomyosarcoma soft tissue sarcomas (NRSTS). Examples of the many types of NRSTS cancers include fibrosarcoma, leiomyosarcoma, liposarcoma, neurofibrosarcoma, peripheral nerve sheath tumors and synovial sarcoma. These cancerous tumors arise in the soft tissues of the body including tendons, muscles, nerves, fatty tissue and fibrous tissue. NRSTS can essentially occur at any site in the body containing these normal types of tissues, such as in the arms and legs, the head and neck region, the chest, abdomen and pelvis. NRSTS accounts for ~ 5 percent of all pediatric cancers.
Certain types of NRSTS are most likely to affect infants (under 1 year of age), while other types are more common in adolescents and young adults. Because soft tissue is expandable, these tumors can sometimes grow rather large before they are felt or cause problems for the patient. Like all cancers, they can invade surrounding tissues and metastasize (spread) to other organs of the body.