What Are Cold Snare Protrusions and Are They a Bad Thing?

What Are Cold Snare Protrusions and Are They a Bad Thing?

Douglas K. Rex, MD, MASGE, reviewing Ishii T, et al. Gastrointest Endosc 2020 Jul 27.

During cold snare polypectomy, removal of larger lesions and/or larger specimens sometimes results in a cold snare protrusion (CSP), appearing as a white cord in the center of the snaring defect. Biopsy studies have shown that while this cord rarely contains residual polyp, it consists of submucosa and muscularis mucosa, which therefore suggests possible incomplete mucosal layer resection and specimen fragmentation during shallow excision. 

The current study evaluated CSPs using a different approach, namely histological assessment of the resected specimens when protrusions occurred versus when they did not. 

Of 1026 evaluated polyps, CSPs occurred in 116 (11.3%). As expected, CSP occurrence was significantly associated with increased polyp size (P=.007) and specimen size (P<.001). The rate of complete endoscopic resection was similar in the CSP and non-CSP groups (57% vs 61%; P=.413). However, specimens were fragmented more often when CSP occurred (40% vs 15%; P<.001), and polyp fragmentation was significantly associated with CSP occurrence (P<.001). 

In the histological assessment, the investigators evaluated the percentage of specimens that had visible muscularis mucosa along the deep margin. Presumably, specimens with less muscularis mucosa along the deep margin would more likely be associated with unresected polyp. The investigators found that the proportion of lesions in which <50% of the deep margin contained visible muscularis mucosa was 49% in the CSP group versus 29% in the non-CSP group (P<.001).

Douglas K. Rex, MD, FASGE


These data suggest that cold snare polypectomy could leave unresected polyp, but trials generally indicate that cold and hot snare polypectomy are equally effective for resecting 10-mm or smaller lesions. Thus, the clinical significance of the findings is currently unclear.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.


Ishii T, Harada T, Tanuma T, et al. Histopathological features and fragmentation of polyps with cold snare defect protrusions. Gastrointest Endosc 2020 Jul 27. (Epub ahead of print) (https://doi.org/10.1016/j.gie.2020.07.040)

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