Various radiological appearances of angiomyolipomas in the same kidney

A 21-year-old woman with tuberous sclerosis presented with abdominal disten sion and flank pain. Imaging studies, including CT and MR imaging, revealed bilateral renal mass lesions, containing fat and suggesting the diagnosis of tuberous sclerosis. However the imaging characteristics of one of these lesions differed from the others with no radiologically detectable fat tiss ue in this solid lesion suggesting renal cell carcinoma. Histopathological examination of this lesion in the left kidney revealed an angiomyolipoma wi th minimal fat tissue. The radiological diagnosis of angiomyolipomas with m inimal fat tissue remains difficult and the differential diagnosis is discu ssed.