Renal angiomyolipoma composed primarily of smooth muscle element: diagnostic considerations.

A case of renal angiomyolipoma composed primarily of smooth muscle element is presented. It was a solitary small tumor without evidence of tuberous sclerosis. The imaging findings including ultrasonography, computerized tomography, magnetic resonance imaging, and angiography were not characteristic of angiomyolipoma, but suggestive of atypical renal cell carcinoma, and a simple nephrectomy was performed. The diagnostic considerations, particularly imaging features of angiomyolipoma, are discussed.