Xanthogranulomatous pyelonephritis in childhood: diagnosis difficulties and success of conservative treatment

Xanthogranulomatous pyelonephritis is an uncommon form of chronic pyelonephritis rarely seen in children. Preoperative diagnosis is difficult and management is still obscure. The authors report on a focal pseudotumoral case and discuss therapeutic modalities. A 2-year-old boy was admitted for a 2-weeks history of fever and right flank pain. Physical examination revealed a right lumbar mass. White blood cell count was 12.800/mm3 and C reactive protein elevated [50 mg/1]. The urine culture was negative. Ultrasonography and computerized tomography demonstrated a focal multilocular cystic mass of the lower polar of right kidney, measuring 80 millimeters, with peripheral enhancement and perirenal involvement. At surgical exploration, a huge abscess of the lower polar of the kidney with dense adhesions to adjacent structures were noted. Excision of the collection and local drainage were performed. Pathologic examination of biopsy specimen confirmed the diagnosis of Xanthogranulomatous pyelonephritis. Intraoperative culture was positive for Escherichia coli. Successful treatment of the lesion was achieved with adjunctive antibiotic therapy. The postoperative course was uneventful over a follow-up period of 2 years. Xanthogranulomatous pyelonephritis should be considered in the differential diagnosis of a renal mass. A first-line conservative treatment must be strongly recommended in pediatric focal cases