Diffuse xanthogranulomatous pyelonephritis in a child with severe complications.

Xanthogranulomatous pyelonephritis is a rare disease in childhood. Because the symptoms and signs are chronic and non-specific, preoperative diagnosis is usually difficult. We report an 8-year-old boy who had an abdominal mass and anemia for more than 6 months. Fever and dyspnea occurred 4 days prior to admission. Ultrasonography revealed an enlarged right kidney with multiple parenchymal hypoechogenic areas, absence of normal parenchymal structures, and perinephric thickening with multiple calcifications. An abdominal computed tomogram demonstrated an irregular, enlarged right kidney with multiple low-density round areas consistent with hydronephrosis and calculi. Diminished excretion of contrast media and a severe perinephric inflammatory reaction were present. Poor right kidney function was demonstrated by Tc99m-diethylenetriamine penta-acetic acid split renal function examination. We diagnosed xanthogranulomatous pyelonephritis preoperatively based on the clinical and radiological features. The child first had drainage of an extrarenal abscess and antibiotic therapy, followed by definitive nephrectomy. The hospital course was complicated with pleural effusion, peritonitis, pelvic abscess, and sepsis. A two-stage nephrectomy requiring less radical resection and decreasing the surgical complications would have been preferable.