Allograft dysfunction in a patient with an odd-looking kidney: case of renal lipomatosis and review of literature.

Renal lipomatosis was diagnosed in a kidney transplant recipient who presented with acute kidney injury (AKI) several years after transplantation. The patient had an odd-looking kidney transplant on ultrasound and computed tomography (CT) scan, showing a medullary mass with resultant compression of the surrounding renal parenchyma. A biopsy of the renal medulla confirmed fatty infiltration of the renal parenchyma. The patient underwent percutaneous nephrostomy and AKI resolved with relief of the obstruction. Renal lipomatosis is a rare condition that should be differentiated from other neoplasms of the kidney. When it occurs in a functioning transplant kidney, the treatment approach proves to be very challenging.