Renal angiomyolipoma with contrast-enhancing elements mimicking renal malignancy: radiographic and pathologic evaluation.

The diagnosis of angiomyolipoma can typically be made on the basis of characteristic computed tomography findings. Varying tissue compositions within an angiomyolipoma can create difficulty in pathologically differentiating benign from malignant lesions. Epithelioid angiomyolipoma is a variant of angiomyolipoma characterized by the presence of epithelioid cells. We report a case of two discrete contrast-enhancing lesions within an enlarging angiomyolipoma that radiographically mimicked malignant elements. This finding presented a diagnostic challenge in terms of selecting medical versus surgical intervention. Surgical excision of the lesions was performed and the pathologic examination revealed a benign angiomyolipoma with epithelioid features.