Incidental capture of rarely diagnosed pediatric tumor: an infant boy with clear cell sarcoma of the kidney.

Clear cell sarcoma of the kidney (CCSK) is an uncommon neoplasm that accounts for less than 5% of all pediatric renal tumors. Compared with Wilms' tumor, CCSK has a higher rate of relapse, greater propensity for bone metastasis, and poorer overall survival. We present the case of a 19-month-old boy with a large renal mass diagnosed incidentally by ultrasonography during surveillance for vesicoureteral reflux. This report describes the rare occurrence of an incidental radiologic capture of CCSK and provides a brief review of disease pathology.