Xanthogranulomatous pyelonephritis in pediatric patients.

We observed xanthogranulomatous pyelonephritis in 5 of 27 nephrectomies (18.5%) performed for end stage pyelonephritis. Two patients were 5 months old or younger, of normal birth weight and the products of uncomplicated full-term pregnancies. In all cases clinical histories and findings were consistent with xanthogranulomatous pyelonephritis yet this diagnosis was suspected prospectively in only 1 case. Our observations, supported by recent literature, suggest that xanthogranulomatous pyelonephritis may occur more commonly than previously reported. In addition, the clinical and pathological expression of this process in the pediatric population appears to be no different from that in adults. The true incidence and presumed chronicity of this process need to be reevaluated in light of recent data.