SMN1 and kidney angiomyolipoma: These researchers found that, in general, although renal angiomyolipomas stained positive for smooth muscle actin and HMB45, the colonic ones stained positive for SMA but very rarely reacted to HMB45.17–19 In our patient's case, the histopathologic appearance was very characteristic of a colonic angiomyolipoma, not necessitating any further histochemical staining.