Large expansile mass at the upper pole of the right kidney, likely at the renal sinus. The mass is partially surrounded by a thin layer of renal sinus fat and the overlying cortex is markedly thinned. The density is equal to the aorta at both phases of imaging. The right renal artery is markedly enlarged and feeds into the mass at its antero-superior margin. No enlarged renal vein. There are a few thin linear calcifications at the margin of the lesion.
No renal calculi or hydronephrosis. The lower pole of the right kidney is normal. Moderate degree of stranding at the renal pelvis and along the proximal ureter.