Abstract

The majority of colorectal carcinomas (95∼100%) are thought to arise from adenomas. Yet colorectal carcinomas may rarely arise de novo. The popular definition of de novo carcinoma is that the lesion should consist exclusively of a carcinoma histologically and contain no adenomatous elements. Without an adenoma-carcinoma sequence, de novo carcinomas have a much higher rate of submucosal invasion, despite their small size. Their speed of growth is thought to be rapid. Some studies have shown that de novo carcinomas might arise as a macroscopically flat or depressed lesion, rather than a protruded one. However, the typical macroscopic findings of de novo carcinomas have not been established. They might be variable macroscopically and include a protruded type. We report a case of de novo colorectal carcinoma that invaded the submucosal layer involving a minute sessile polyp only 3 mm in diameter, which was removed by endoscopic mucosal resection. (Korean J Gastrointest Endosc 2011;42:109-112)

• Keywords: Submucosal invasive colorectal cancer, Early colorectal carcinoma, Minute sessile polyp, De novo carcinoma