Soft tissue sarcomas are a group of cancers that begin in areas that surround, connect or support the body’s structure or organs. This includes:
- Connective tissue
- Blood vessels
- Lymph vessels
The most common locations of soft tissue sarcomas are the arms and legs. But they also can grow in the head and neck area, chest, abdomen and pelvis. Soft tissue sarcoma can occur in children and adults. This information is about soft tissue sarcoma in children.
Rhabdomyosarcoma is the most common childhood soft tissue sarcoma. It grows in the muscles attached to the skeleton. According to the American Cancer Society, about 340 children in the nation are diagnosed with rhabdomyosarcoma each year. It makes up 3% of childhood cancers and 2% of adolescent cancers.
Other soft tissue sarcomas
Other childhood soft tissue tumors are sometimes called non-rhabdomyosarcoma soft tissue sarcomas (NRSTS). All together, this group of cancers makes up about 4% of pediatric cancers. Many types of exist. They are classified by what part of the body they started in. The cells in each type are different
Other than rhabdomyosarcoma, the most common soft tissue sarcomas in children are:
Fat tissue tumors: Liposarcoma in children is usually low grade and grows slowly. The most common type is called myxoid liposarcoma.
Bone and cartilage tumors: Extraskeletal chondrosarcoma develops in the cartilage of the bone and is more common in adults.
Connective tissue tumors, including:
- Desmoid tumors or aggressive fibromatosis, which usually grows slowly and is unlikely to spread to other parts of the body. Children with the genetic condition familial adenomatous polyposis (FAP) are at higher risk.
- Fibrosarcoma, which is usually found in children under 4, especially infants. Sometimes it is found in an ultrasound during pregnancy. Tumors tend to be large and grow quickly, but they usually do not spread.
Muscle tumors: Leiomyosarcoma is associated with the Epstein-Barr virus in children with HIV/AIDS. Survivors of retinoblastoma are also at higher risk.
Skin tumors (also called fibrohistiocytic tumors): Plexiform fibrohistiocytic tumors begin as a painless mass on or under the skin of the arm, hand or wrist. Undifferentiated pleomorphic sarcoma tends to develop in the arms or legs of children who have had radiation therapy or retinoblastoma.
Nerve tumors: Malignant peripheral nerve sheath tumors grow in the covering of nerves outside the brain and spinal cord. Children with the genetic condition neurofibromatosis type 1 (NF1) are at higher risk.
Tumors of unknown origin: Synovial sarcoma tumors are found in the joints of the legs or arms, or in the head, neck or trunk. Children under 10 with small tumors have the best chance for successful treatment.
Blood vessel tumors, including:
- Angiosarcomas, which grow quickly in lymph or blood vessels.
- Epithelioid hemangioendotheliomas, which usually develop in infants in the liver. They typically are benign (not cancer).
Pediatric soft tissue sarcoma risk factors
Anything that increases your child’s likelihood of developing soft tissue sarcoma is a risk factor. These include:
- Inherited genetic conditions such as:
- Neurofibromatosis type 1 (NF1)
- Li-Fraumeni syndrome
- Inherited retinoblastoma
- Werner syndrome
- Familial adenomatous polyposis (FAP)
- HIV/AIDS and Epstein-Barr virus
- Age: Teenagers and infants under 1 year of age are at higher risk.
If your child has a risk factor for soft tissue sarcoma, it does not mean your child will develop the disease. However, if any of the above disorders run in your family, be sure to tell your child’s doctor. Genetic testing may be suggested.
Some soft tissue sarcomas can be passed down from one generation to the next. Genetic counseling may be right for you. Learn more about the risk to you and your family on our genetic testing page.