Rhabdomyosarcoma is a malignant (cancerous), soft tissue tumor found in children. The most common sites are the structures of the head and neck, the urogenital tract, and the arms or legs. The cause of rhabdomyosarcoma is unknown. It is a rare tumor with only several hundred new cases per year throughout the United States. Some children with certain birth defects are at increased risk, and some families have a gene mutation that elevates risk. However, the vast majority of children with rhabdomyosarcoma do not have any known risk factors.
