Endoscopic management of colorectal polyps: From benign to malignant polyps

Table 2 Japan Narrow-band imaging Expert Team classification system

	Type 1	Type 2A	Type 2B	Type 3
Vessel pattern	Invisible	Regular caliber and distribution (meshed/spiral)	Variable caliber, irregular distribution	Loose vessel areas, interruption of thick vessels
Surface pattern	Uniform dark or white spots similar to surrounding mucosa	Regular (tubular/branched/papillary)	Irregular or obscure	Amorphous areas
Most likelyhistology	Hyperplastic or sessile serrated polyps	Low grade dysplasia	High grade dysplasia/shallow submucosal invasive cancer	Deep submucosal invasive cancer

This system uses vessel and surface pattern evaluation under magnified endoscopy with narrow-band imaging to predict the most likely polyp histopathology.