Efficiency of endocytoscopy in differentiating types of serrated polyps

BackgroundAccurate endoscopic criteria are needed to differentiate serrated polyps, including hyperplastic polyp (HP), sessile serrated adenoma/polyp (SSA/P), and traditional serrated adenoma (TSA), because some are precursors of colorectal cancers.ObjectiveTo determine the endocytoscopic features of each type of serrated polyp, especially the shapes of lumens and nuclei.DesignRetrospective study.SettingSingle, tertiary-care referral center.PatientsPatients who underwent removal of serrated polyps from May 2005 to December 2012.InterventionEndocytoscopy was performed. Endocytoscopic images were evaluated by assessing the shapes of the lumens and nuclei of the target lesions.Main Outcome MeasurementsThe significant endocytoscopic features in differentiating among types of serrated polyps.ResultsOf the 58 eligible lesions, 27 were classified as HP, 12 as SSA/P, and 19 as TSA. Most HPs (77.8%) had star-like lumens, and most SSA/Ps (83.3%) had oval lumens. The lumens of TSAs were serrated (31.6%) or villous (68.4%), with both shapes seen only in TSAs. Most HPs (92.6%) and SSA/Ps (75.0%) had small, round nuclei, and all TSAs had fusiform nuclei. Features significantly differentiating TSAs from HPs and SSA/Ps were the presence of fusiform nuclei (P < .001) and villous (P < .001) and serrated (P = .002) lumens. The presence of oval lumens was significantly characteristic of SSA/Ps (P < .001), and the presence of star-like lumens was significantly characteristic of HPs (P < .001).LimitationsRetrospective design. Single-center study.ConclusionThe shape of lumens and nuclei on endocytoscopy can efficiently differentiate among the different types of serrated polyps. (Clinical trial registration number: UMIN Clinical Trials Registry UMIN000007850.)