Distinguishing the Endoscopic Characteristics of Sessile Serrated Lesions and Microvesicular Hyperplastic Polyps from Goblet Cell-Rich Hyperplastic Polyps

Aims Among colorectal serrated polyps (SPs), sessile serrated lesions (SSLs) and hyperplastic polyps (HPs) show a similar endoscopic appearance on endoscopy [1]. However, the endoscopic distinctions between the two categories, microvesicular HP (MVHP) and goblet cell-rich HP (GCHP) are not well understood. Therefore, we compared the endoscopic features of SSL, MVHP, and GCHP.

Methods This retrospective, cross-sectional study was conducted at the Toyoshima Endoscopy Clinic. We examined the polyp size, location, Paris classification type, mucus cap, indistinct border, expanded crypt opening, varicose microvascular vessels, and Japan NBI expert team (JNET) classification type. Multivariable analysis of each endoscopic finding using a binomial logistic regression model determined the factors that predicted SP histology.

Results A total of 670 SPs were enrolled in this study, comprising 159 SSLs, 361 MVHPs, and 150 GCHPs. Mean polyp size was 6.42 mm. SPs located in the proximal colon accounted for 70.3%. On comparing the SSL+MVHP group and GCHP, a mucus cap (partial regression coefficient 1.705, 95% confidence interval [CI] 1.141-2.269), expanded crypt opening (1.828, 1.159-2.496), and varicose microvascular vessels (1.270, 0.590-1.949) were more often observed in SSL+MVHP group compared with GCHP. Mucus cap, expanded crypt opening, and varicose microvascular vessels were each assigned 1 point and the sum of the points was defined as endoscopic SP score. Of the endoscopic SP score, the area under the receiver operating characteristic curve (AUC) was 0.83 (95% CI 0.81-0.86) and the optimal cut-off value was 1; the sensitivity, specificity, and positive predictive value were 81.5%, 74.7%, 91.8%, respectively. In the comparison between MVHP and GCHP, a mucus cap (1.564, 0.988–2.139), expanded crypt opening (1.802, 1.127-2.477), and varicose microvascular vessels (1.288, 0.596-1.980) were more often found in MVHP in contrast to GCHP. The AUC of the endoscopic SP score was 0.80 (95% CI 0.76-0.83) and the optimal cut-off value was 1; the sensitivity, specificity, and PPV were 76.7%, 74.7%, and 87.9%, respectively. When comparing SSL and MVHP, SSLs were more likely to be in the proximal colon (0.662, 0.087-1.237) and were larger (0.198, 0.134-0.262) than MVHPs. No significant differences were observed in other endoscopic findings.

Conclusions SSL and MVHP had distinct endoscopic appearances including mucus cap, expanded crypt opening, and varicose microvascular vessels, compared to GCHP. There were no differences in endoscopic findings between SSL and MVHP, other than their location and size. Thus, interestingly, MVHP and GCHP, while belonging to the same HP category, displayed different endoscopic appearances. Conversely, SSL and MVHP despite belonging to different histopathological categories, demonstrated striking endoscopic similarities. Treating MVHP and GCHP as distinct entities may facilitate the endoscopic diagnosis of SPs.

 

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Conflicts of interest

Authors do not have any conflict of interest to disclose.

• References

• 1 Zessner-Spitzenberg J, Waldmann E, Jiricka L. et al. Comparison of adenoma detection rate and proximal serrated polyp detection rate and their effect on post-colonoscopy colorectal cancer mortality in screening patients. Endoscopy 2023; 55: 434-441

Publication History

Article published online:
15 April 2024