Xanthogranulomatous pyelonephritis in children.

Xanthogranulomatous pyelonephritis usually occurs in women 50 to 60 years old, and has the distinct clinical presentation suggestive of a renal mass. Since 1963 an increasing number of children with xanthogranulomatous pyelonephritis have been reported in the literature, with data suggesting that the characteristics of the disease are different from those in adults. We compared our children with xanthogranulomatous pyelonephritis to adults who had been described in the literature and to our cases of chronic pyelonephritis to determine whether xanthogranulomatous pyelonephritis in children is an entity as clearly different from chronic pyelonephritis as it is in adults. Twenty-one cases were eliminated from the study because of incomplete charts. We found 39 cases in which nephrectomy had been done for an anatomical diagnosis of chronic or xanthogranulomatous (8) pyelonephritis. Average age at presentation, duration of clinical course and sex distribution were similar in both groups. The left kidney was involved more often in both groups. Severe malnutrition, urolithiasis, reno-cutaneous fistula and negative urine cultures were more frequent in cases of xanthogranulomatous pyelonephritis, while obstructive nonlithiasic uropathy occurred more often in cases of chronic pyelonephritis. Microorganisms were similar in both groups and Escherichia coli was isolated most frequently. All cases of xanthogranulomatous pyelonephritis were of the diffuse type with areas corresponding to all histological stages. Our study suggests that perhaps in children xanthogranulomatous pyelonephritis occurs the same as chronic pyelonephritis, and is determined possibly by an affected immune response secondary to malnutrition and by the presence of urolithiasis.