rhabdomyosarcoma (Monarch Disease Ontology identifier MONDO_0005212) is a rare aggressive malignant mesenchymal neoplasm arising from skeletal muscle. It usually occurs in children and young adults. Only a small percentage of tumors arise in the skeletal muscle of the extremities. The majority arise in other anatomical sites. Also known as: rhabdomyosarcoma (disease), rhabdomyosarcoma, malignant.