Underwater endoscopic mucosal resection for a colonic polyp located at the scar after endoscopic band ligation

A man in his 70s was admitted to our hospital for detailed investigation of bloody stool. Emergency colonoscopy showed multiple colonic diverticula, one of which had stigmata of recent hemorrhaging, and endoscopic band ligation (EBL) was performed ([Fig.1 a]) [1].

Fig. 1 Endoscopic views showing: a band ligation being performed for a bleeding colonic diverticulum with the stigmata of recent hemorrhaging visible; b the colonic polyp seen at the scar 1 month after endoscopic band ligation; c the polyp, seen on narrow-band imaging, being snared underwater; d the mucosal defect after underwater endoscopic mucosal resection with no evidence of residual sites around the margin.

A follow-up colonoscopy was conducted 1 month after EBL. The diverticulum had scarred over, but a colonic polyp (7 mm, Is type) was detected at the scar ([Fig. 1 b]). Because it was difficult to carry out conventional endoscopic mucosal resection (EMR), we decided to perform underwater EMR (UEMR) ([Video 1]). We filled the lumen of the colon with water, which allowed the lesion to be clarified using narrow-band imaging, then snared and resected the lesion with Endocut Q mode (effect 3, duration 2, interval 4; VIO300D, ERBE Germany) ([Fig. 1 c]). No residual neoplastic sites were seen around the margin of the mucosal defect ([Fig. 1 d]). The pathological diagnosis for the resected specimen was a low grade adenoma with negative horizontal and vertical margins ([Fig. 2]).

Video 1 An underwater endoscopic mucosal resection technique is used for a colonic polyp located at the scar after prior endoscopic band ligation.

Fig. 2 Histology of the resected polyp consistent with a diagnosis of a low grade adenoma.

UEMR is reported to be useful for removing polyps without submucosal injection. This technique has been applied to duodenal adenomas [2] and to several unique or difficult cases [3] [4]. This was a unique case in which conventional EMR for a colonic polyp was difficult because of the scarring after EBL. Filling the lumen with water made it easier to observe and snare the lesion by expanding the convergence of the mucosa. UEMR is a safe and effective technique in cases where conventional EMR cannot be performed because of scarring, such as after endoscopic or surgical treatment.

Endoscopy_UCTN_Code_TTT_1AO_2AG

Competing interests

None

• References

• 1 Higashi R, Kinugasa H, Nakagawa M. Endoscopic band ligation for colonic diverticular bleeding. Dig Endosc 2018; 30: 399
• 2 Yamasaki Y, Uedo N, Takeuchi Y. et al. Current status of endoscopic resection for superficial nonampullary duodenal epithelial tumors. Digestion 2018; 97: 45-51
• 3 Takeuchi Y, Tonai Y, Ikeda K. Underwater endoscopic resection for a superficial polyp located at the anastomosis after surgical colectomy. Dig Endosc 2017; 29: 67-68
• 4 Kono Y, Sakae H, Okada H. Underwater endoscopic mucosal resection for gastric polyp. Dig Endosc 2018; 30: 525