Endoscopic Characteristics of Colorectal Serrated Lesions

Background/Aims: With the recent changes of pathological concepts, colorectal serrated lesions can, be now divided into traditional serrated adenoma, typical hyperplastic polyp and sessile serrated polyp. The aim of this study is to clarify the endoscopic differences among these three groups. Methodology: A total number of 362 serrated lesions larger than 5mm were evaluated. These were detected with ordinary view and observed also with magnifying chromoendoscopic view. The final pathologic diagnosis of the resected specimens was made blinded. Results: There were significant differences between traditional serrated adenoma and sessile serrated polypconcerning location, configuration and color. In chromoendoscopy, most of sessile serrated polyps and typical hyperplastic polyps showed star-like pattern, in contrast with traditional serrated adenomas most of which had fernor pinecone-like pattern. The differential diagnosis between traditional sessile polyp and the other two was possible with high accuracy. On the other hand, endoscopic distinction between sessile serrated polyp and typical hyperplastic polyp was not easy, except that the location and size were significantly different. Conclusions: We can endoscopically differentiate between traditional serrated adenoma and sessile serrated polyp or typical hyperplastic polyp, but it is difficult to differentiate between the latter two.