The presented case shows radiological features of renal replacement lipomatosis which is a rare condition characterised by fatty tissue proliferation in the renal sinus and perinephric space with marked destruction/atrophy of renal parenchyma (due to chronic inflammation).

It shows increased renal sinus fat as well as perirenal fat and marked atrophic changes of the renal parenchyma with the remaining peripheral part delineating the renal outline. On the contrary, the renal parenchyma is preserved in renal sinus lipomatosis.

The presence of renal parenchymal atrophy distinguishes this disease from other aetiology of fibro-fatty proliferation in and around the kidney, as in obesity or Cushing's disease and excessive corticosteroid therapy.