Primary squamous cell carcinoma of the renal pelvis masquerading as pyonephrosis: a case report.

Squamous cell carcinoma of the renal pelvis is a rare tumor, which is usually associated with nephrolithiasis. It is rarely associated with pyonephrosis. We report the case of a 69-year-old man who presented with features of pyonephrosis and underwent nephrectomy. The postoperative histological evaluation revealed an unsuspected squamous cell carcinoma of renal pelvis with a concomitant pyonephrosis. The rarity of this tumor in the absence of renal calculi and its association with pyonephrosis is highlighted.