Xanthogranulomatous pyelonephritis in a 1-year old boy.

Xanthogranulomatous pyelonephritis (XGP) is a rare, chronic inflammatory lesion of the kidney associated with both chronic infection and obstruction. Most common in middle-aged females, it is important to recognize in children because it may be confused with childhood renal malignancies particularly Wilms' tumor. We report a case of a 1-year old male with antenatally detected and postnatally confirmed hydronephrosis. Further investigation revealed a left incomplete duplex collecting system with obstructing lower pole stones, pelvicaliectasis and widespread foci of calcification. He underwent a left nephroureterectomy with the pathological report noting XGP.