Renal replacement lipomatosis and xanthogranulomatous pyelonephritis: differential diagnosis.

Renal replacement lipomatosis (RRL) is a relatively uncommon entity, although misdiagnosis mainly with xanthogranulomatous pyelonephritis (XGP) due to lack of awareness by urologists, radiologists, and pathologists may be responsible for underreporting1,2. We illustrate a case of RRL that was initially misdiagnosed as XGP, and compare it with a classic case of XGP, underscoring the similarities and the differences between them.