A unique feature of this tumor category is the coexpression of smooth muscle and melanocytic markers, including HMB-45, Melan-A, MITF, SMA, desmin, and caldesmon.42,44 “Fat-rich” angiomyolipomas have been described, defined by more than 75% of tumor composed of mature fat.45 In a subset of our cases, we found thick-walled blood vessels with associated fibrous bands in the lobules of adipocytes. This evidence concerns the gene SMN1 and angiomyolipoma.