Various appearances of multiple angiomyolipomas in the same kidney in a patient without tuberous sclerosis

Abstract

Angiomyolipoma (AML) is the most common benign renal tumor. It is usually found incidentally in an isolated form as a solitary small echogenic lesion. Less commonly, it is part of the tuberous sclerosis complex and is seen as multiple lesions in both kidneys. Although most AMLs are echogenic because of the fat component, a small number of these tumors have minimal fat content and may appear relatively hypoechoic. Conversely, renal cell carcinoma (RCC) is usually hypoechoic and easily differentiated from AML, although recent reports indicate that small echogenic RCCs may be more common than previously thought. We report a case of multiple AMLs in the kidney of a patient without tuberous sclerosis, in whom one of the tumors mimicked an RCC.