<prompt> Most common site of childhood rhabdomyosarcoma isTrunkGenitourinary systemExtremitiesHead and neck  <response>: Rhabdomyosarcoma usually begins in muscles that are attached to bones and that help the body move. Rhabdomyosarcoma is the most common type of soft tissue sarcoma in children. It can begin in many places in the body. Ref robbins 9e p510 