CT appearance of giant renal angiomyolipoma.

Renal angiomyolipomas are rare benign tumors readily identified by computed tomography due to their high fat content. When they attain giant proportions other fatty neoplasms, specifically liposarcomas, cannot be excluded based on the radiographic findings. A case in which a notch defect in the lateral border of the kidney was the single most important clue as to the intrarenal origin of the mass and led to the correct pre-operative diagnosis is presented.