Characterization and significance of protrusions in the mucosal defect after cold snare polypectomy

Background Cold snare polypectomy (CSP) is widely practiced; however, the endoscopic features of the CSP mucosal defect have not been studied. In particular, protrusions within the cold snare defect (CSDPs) may create concern for residual polyp. The frequency and constituents of this phenomenon are unknown. Objective To describe the frequency, predictors, and histologic constituents of CSDPs. Design Prospective observational study. Setting Tertiary-care hospital endoscopy unit. Patients Eighty-eight consecutive patients undergoing CSP for a polyp ≤ 10 mm in size. Intervention Inspection of the cold snare mucosal defect with high-definition white light and biopsy sampling of CSDPs for separate histologic assessment, when present. Main Outcome Measurement Frequency and constituents of CSDPs. Results Two hundred fifty-seven consecutive polyps ≤ 10 mm in size were removed in 88 patients (50 men [57%], mean age 63 years). Polyps were predominately adenomatous (162, 63%), located in the proximal colon (159, 62%) and flat (200, 78%). Mean lesion size was 5.5 mm (range, 2-10 mm). High-grade dysplasia was present in a single polyp for which the defect was bland. CSDPs occurred in 36 polypectomies (14%). CSDPs were associated with polyp size ≥ 6 mm (odds ratio, 3.7; P < .001 multivariable analysis) but not age, sex, lesion, histopathology, morphology, or location. Histopathologic examination of CSDPs revealed submucosa in 34 (94%) and muscularis mucosa in 29 (80%). No residual adenomatous or serrated polyp tissue was detected. Limitations Single-center study. Small number of polyps with high-grade dysplasia. Conclusion Protrusions are common within the CSP mucosal defect and are associated with polyp size ≥ 6 mm. CSDPs do not represent vascular structures, do not contain residual polyp, and are not associated with adverse outcomes in short-term follow-up. However, CSDPs represent incomplete mucosal layer resection.