Simultaneous renal cell carcinoma and squamous cell carcinoma of kidney.

A unique case of a collision tumor of the kidney composed of a renal cell carcinoma and a squamous cell carcinoma is reported. Although a few cases of combined tumors of the kidney have been reported previously, we were unable to find any similar case in the literature. Squamous cell carcinoma of the kidney usually behaves aggressively. Early diagnosis and surgical treatment before the tumor has extended beyond the capsule offer the best hope of cure.