A CASE OF PRIMARY EARLY SIGNET-RING CELL CARCINOMA OF THE COLON

Abstract

We experienced a primary signet-ring cell carcinoma of the colon localized in the mucosal layer. A 64-year-old man visited our hospital with a complaint of alternating bowel habits. Digital examination of the rectum suggested a polypoid lesion just above the anus. Total colonoscopy revealed two elevated lesions; the one in the transverse colon and the other in the rectum. The former was a IIa+IIc type lesion and the latter was a polypoid lesion endoscopically. Histologically the former was signet-ring cell carcinoma localized in the mucosal layer, 6mm in diameter, and the latter was well-differentiated adenocarcinoma. We reviewed 6 cases of early colorectal signet-ring cell carcinoma reported in Japan. In 4 cases (67%) the lesions were flat or depressed which incidence was markedly high compared with that in common type of colorectal cancer. It is probable that signet-ring cell carcinoma is flat or depressed from the initial stage and later invades the submucosal layer rapidly. Therefore, endoscopist must keep it in his mind and perform total colonoscopy carefully.