Xanthogranulomatous pyelonephritis in a functioning kidney. A case report

A 34-year-old woman with xanthogranulomatous pyelonephritis mimicking a renal tumour is presented. Preoperative examinations including renal ultrasonography, computed tomography, renal angiography and fine needle biopsy could not exclude malignancy. The diseased kidney had good function and there was no history or signs of urinary tract infection or calculi. During operation a frozen section biopsy showed xanthogranulomatous pyelonephritis and a kidney-saving enucleation of the tumour was performed. The patient recovered uneventfully with good kidney function on the operated side.