Xanthogranulomatous pyelonephritis-mimicking renal mass in 5-month-old child.

Xanthogranulomatous pyelonephritis is a rare, chronic inflammatory lesion of the kidney associated with chronic infection and obstruction. It is uncommon in children and extremely rare in infants. Because of its rarity, the condition is often not considered in the differential diagnosis of a renal mass in children. We report a case of a 5-month-old boy presenting with fever and a left renal mass. The findings from radiologic investigations were suggestive of a renal mass and urine culture suggestive of urinary tract infection. Left radical nephrectomy was performed with difficulty because of the dense adhesions to the adjacent structures. Histopathologic examination confirmed the diagnosis of xanthogranulomatous pyelonephritis.