There are 2 main types of rhabdomyosarcoma.
Embryonal rhabdomyosarcoma is the most common type of rhabdomyosarcoma diagnosed in children. It makes up about 50%–70% of all rhabdomyosarcomas diagnosed in children. It is more common in younger children and most commonly diagnosed in children under the age of 10 years.
Alveolar rhabdomyosarcoma can occur more often in older children or teens. About 20% of all rhabdomyosarcomas diagnosed in children are alveolar. Alveolar rhabdomyosarcoma can occur anywhere in the body but most commonly develops in the muscles of the arms and legs, muscles of the trunk of the body (chest and abdomen) and the area around the anus.
Anaplastic rhabdomyosarcoma rarely occurs in children.
Sometimes doctors can’t tell the type of soft tissue sarcoma because the cells don’t look like a specific type of cell. This is called undifferentiated sarcoma. Doctors may group undifferentiated sarcomas with rhabdomyosarcoma.