Microscopic findings from a resected colon specimen. The tumor developed from the muscular layer of the colon (A). Histological and immunohistochemical findings for the colon and liver tumors were similar (B-H). The blood vessel wall and nerve tissues were positive for CD34 (G) and S-100 (H), respectively. A and B, H&E; C, SMA; D, desmin; E, h-caldesmon; F, C-kit; G, CD34; and H, S-100.