Primary Squamous Cell Carcinoma of the Renal Pelvis: A Rare Complication of Xanthogranulomatous Pyelonephritis.

Xanthogranulomatous pyelonephritis is a rare disease resulting from chronic inflammation and infection of the renal parenchyma. It usually arises as a consequence of obstructive chronic pyelonephritis. Primary squamous cell carcinoma of the renal pelvis is a distinct pathology, very rare in clinical practice, with a well-established association with xanthogranulomatous pyelonephritis. The authors present the case of a 57-year-old woman with chronic pyelonephritis containing xanthogranulomatous features. Subsequent workup revealed a concomitant, unsuspected, primary squamous cell carcinoma of the renal pelvis. With this case, the authors intend to emphasize and reinforce the need to be alert to an uncommon association between two rare diseases due to its diagnostic, therapeutic, and prognostic implications.