Imaging of retroperitoneal rhabdomyosarcoma mimicking hypernephroma.

Malignant tumors that arise in the perinephric space often present a diagnostic dilemma. These retroperitoneal tumors may resemble renal carcinomas, extrahepatic lymphoma, metastatic disease, or tumors arising in other retroperitoneal organs. We present a case of a patient with a primary retroperitoneal rhabdomyosarcoma who had an extensive diagnostic workup prior to surgical intervention that was thought to be consistent with an aggressive renal cell carcinoma.