Xanthogranulomatous pyelonephritis associated with a congenital caliceal diverticulum

We report a rare case of xanthogranulomatous pyelonephritis occurring in a caliceal diverticulum in a 1-year-old child. She presented with recurrent urinary tract infections. A computed tomography scan demonstrated an enhancing cystic lesion in the left kidney. At open exploration, a caliceal diverticulum was found with a very stenotic opening into the renal pelvis. The diverticulum was enucleated, and the pathologic examination confirmed xanthogranulomatous pyelonephritis in the parenchyma surrounding the diverticulum. The child did well postoperatively with no recurrence of her urinary tract infections.