Endoscopic Features of Sessile Serrated Adenoma/Polyps under Narrow Band Imaging: A Retrospective study.

OBJECTIVE: Sessile serrated adenoma/polyps (SSA/Ps) are recognized as precancerous lesions in the colon and resemble hyperplastic polyps (HPs). Definite endoscopic features under narrow band imaging (NBI) with or without magnification may help differentiate between these two lesions. Our study was designed to identify specific endoscopic features of SSA/Ps by NBI.

METHODS: A total of 199 patients with histopathologically proven colorectal SSA/Ps or HPs after polypectomy were enrolled. Magnifying and non-magnifying NBI pictures of 206 matching lesions were evaluated by 2 non-expert endoscopists and1expert endoscopist using various endoscopic characteristics retrospectively.

RESULTS: A cloud-like surface and dilated and branching vessels (DBVs) were significant endoscopic features that had a 6.48-fold and 7.95-fold increasing risk, respectively, by multivariate analysis in SSA/Ps compared to HPs. The combination of these two factors could improve diagnostic specificity to 96%, and the area under receiver-operating characteristic curves indicated certain accuracy, as well. However, it seemed that the presence of black dark spots (OR: 1.93; 95% CI: 0.94-4.00) was not a definite feature in differentiating these two lesions after multivariate analysis. Neither a mucus cap nor CP-II type meshed capillary vessels showed statistical significance in differentiating SSA/Ps from HPs (P = 0.590 and 0.293, respectively).

CONCLUSIONS: A cloud-like surface and DBVs were two good individual indicators for SSA/Ps compared with other three endoscopic findings. A combination of these two factors under NBI with or without magnification showed better diagnostic performance than when used alone.