Fig. 3

Macroscopic study of the surgical specimen after formalin fixation. Sigmoidectomy specimen showed a tumor measuring 110 × 95 mm; it had a coral-reef-like surface and with numerous soft, worm-like polyps. A solid 30-mm mass, surrounded by these polyps, developed on the anterior wall of the sigmoid colon (white arrowhead). a A solid mass did not spread to the serosa (white arrowhead). The anterior wall was thickened with several diverticulitis (black arrow). b–d The tumor was almost constituted with numerous soft, worm-like polyps. Histopathological findings of these polyps are shown in Fig. 4