Coexistent xanthogranulomatous pyelonephritis and massive replacement lipomatosis of the kidney: CT diagnosis.

Replacement lipomatosis (RPL) is seen in patients in whom renal parenchyma is destroyed due to chronic calculous disease and inflammation. The triggering mechanism for xanthogranulomatous pyelonephritis (XGP) is also the same. We report a case in which RPL and XGP coexist in the same kidney. To our knowledge, this coexistence has not been previously reported.