Xanthogranulomatous pyelonephritis (XGP) in childhood and infancy - clinicopathological features of five cases

Abstract

XGP is an unusual chronic inflammatory condition, which most often affects women between 50-60 years of age. Predisposing factors include infection, calculi and obstructive uropathy. Due to its rarity in children, it is not often considered as a cause of chronic renal inflammatory disease. Review of surgical and autopsy files at the AMCWC over a 28 year period from 1964-91 revealed only 5 cases, the clinicopathological details of which are detailed below. 1) A 3mo malnourished boy with a duplex ureter, vesicoureteric reflux, and renal cytomegalovirus (CMV) infection 2) A 3mo girl with multiple urinary tract infections, a duplex ureter, hydroureter, distal ureteric stricture and upper pole abscess, 3) A 6mo boy with hydroureteronephrosis and renal scarring, 4) A 6yo girl with multiple urinary tract infections, hydroureteronephrosis and renal scarring, and 5) A 13 yo girl with chronic pyelonephritis. 3 total, and 2 partial, nephrectomy specimens were received, 4 of which showed yellow areas on sectioning. All cases demonstrated typical features of XGP with renal parenchyma effaced by a mixed acute and chronic inflammatory infiltrate which included prominent aggregates of foamy histiocytes containing eosinophilic inclusions. Other changes included tubular atrophy, glomerular sclerosis and interstitial fibrosis. No Michaelis-Gutman bodies were seen and staining for iron and calcium was negative. No calculi were present. This study, 1) confirms the association of XGP with chronic infection and reflux in childhood and infancy, 2) raises the possibility of an altered immune response in the pathogenesis of XGP in the infant with malnutrition and concomitant CMV infection, and 31 demonstrates that XGP should be considered in the differential diagnosis of chronic inflammatory conditions of the kidney in very early infancy.