This case is rhabdomyosarcoma, no question. But, what type? From the pictures, it looks more like a solid variant of alveolar rhabdomyosracoma rather than a embryonal rhabdomyosarcoma. FISH or cytogenetic studies (which are essential for soft tissue tumors) will be very helpful in classifying this tumor. Alveolar rhabdomyosarcoma has traslocation invoving the FKHR gene on chromosome 13. It is very important to distinguish  alveolar rhabodo vs. embryonal type and the genetic abberation, since treatment and prognosis are different depend on them.