Early-stage primary signet ring cell carcinoma of the colon

Figure 1 Initial colonoscopic findings (from another hospital). Colonoscopic examination revealed a IIa-like, ill-defined and flatly elevated 5-mm tumor in the cecum (arrow).

Figure 2 Colonoscopic findings at this hospital. A: Colonoscopic examination revealed a IIa-like, ill-defined and flatly elevated 9-mm residual tumor in the cecum; B: Narrow band imaging shows the lesion more clearly.

Figure 3 Resected specimen by endoscopic mucosal resection. The resected specimen was 10 mm in diameter.

Figure 4 Scanning view of the endoscopic mucosal resection site. Histologically, the resected specimen showed diffusely infiltrated signet ring cells in the lamina propria without venous or perineural invasion. A: hematoxylin/eosin staining, × 40; B: hematoxylin/eosin staining, × 400.

Figure 5 Gross findings. The mucosal surface of the cecum showing an ill-defined irregularly-shaped scar (probably the endoscopic mucosal resection site). The remaining mucosa showing multiple polyps and previous polypectomy sites.