Renal angiomyolipoma with pseudocapsule mimicking renal cell carcinoma

Abstract We present a case of renal angiomyolipoma with pseudocapsule mimicking renal cell carcinoma. Axial in-phase and opposed-phase gradient-echo magnetic resonance (MR) images showed that the signal intensity of the lesion is hypointense on the opposed-phase image compared with that on the in-phase image, confirming the presence of lipid in the lesion. Axial T2-weighted fast spin–echo MR imaging showed the lesion as slightly hyperintense relative to adjacent renal parenchyma. On T2-weighted MR imaging, a hypointense rim surrounded the lesion.