Idiopathic renal replacement lipomatosis.

Renal replacement lipomatosis (RRL) is a rare disorder which exhibits extensive proliferation of fatty tissue within the renal sinus, hilum, and perirenal region. The pathogenesis of this entity is unknown, though association with aging, renal atrophy, longstanding chronic urinary infections has been noted. Although imaging modalities may suggest the diagnosis of this entity, it is histopathology that clinches the diagnosis most accurately. We report a case of a 52 year old male who presented with nonfunctioning kidney and was histopathologically confirmed to be a case of renal replacement lipomatosis.