Xanthogranulomatous Pyelonephritis.

Xanthogranulomatous pyelonephritis (XPN) is an variant of chronic pyelonephritis difficult to differentiate from renal malignancy on preoperative evaluation.We report an unusual case of XGP occurring in an immunocompetent patient in the absence of either urinary obstruction or nephrolithiasis, presenting as a diagnostic dilemma.