Underwater endoscopic resection of a neuroendocrine rectal tumor

The endoscopic resection of rectal neuroendocrine tumors (NETs) results in good long-term outcomes [1]. Many techniques for the endoscopic resection of rectal NETs have been described, including polypectomy, endoscopic mucosal resection (EMR), and recently EMR with band ligation [2], endoscopic submucosal dissection [3], and even transanal endoscopic microsurgery [4]. Underwater endoscopic resection is a simple and inexpensive new technique that has been used for the treatment of polyps and flat lesions [5]. We present a case of rectal NET resected with an underwater technique ([Video 1]).

Underwater endoscopic resection of a neuroendocrine rectal tumor.

A 51-year-old woman was referred for the endoscopic treatment of a distal rectal NET. Colonoscopy revealed a yellowish, hardened, 10-mm lesion with a subepithelial aspect, compatible with NET ([Fig. 1]). Water was infused until the rectum lumen was completely filled ([Fig. 2]). An opened snare (SnareMaster; Olympus, Tokyo, Japan) was pushed against the rectal wall to capture a safe margin of normal mucosa ([Fig. 3]). Forced coagulation was used for the initial cutting, and endocut mode (ERBE Elektromedizin, Tübingen, Germany) was then used to complete the resection.

Fig. 1 Neuroendocrine rectal tumor in a 51-year-old woman.

Fig. 2 Underwater appearance of the same lesion.

Fig. 3 Underwater resection with a snare.

In the post-procedural examination, no sign of perforation or residual lesion was observed ([Fig. 4]). Histologic examination of the specimen revealed a well-differentiated grade 1 NET invading the deep submucosal layer with tumor-free resection margins and without angiolymphatic or perineural invasion.

Fig. 4 Appearance after resection, with no residual lesion.

Underwater endoscopic resection of rectal NET can be a new treatment option and was feasible in this case. Case series are needed to confirm the efficacy of this technique.

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• References

• 1 Sekiguchi M, Sekine S, Sakamoto T et al. Excellent prognosis following endoscopic resection of patients with rectal neuroendocrine tumors despite the frequent presence of lymphovascular invasion. J Gastroenterol May 5. [Epub ahead of print]. DOI: 10.1007/s00535-015-1079-7.
• 2 Mashimo Y, Matsuda T, Uraoka T et al. Endoscopic submucosal resection with a ligation device is an effective and safe treatment for carcinoid tumors in the lower rectum. J Gastroenterol Hepatol 2008; 23: 218-221
• 3 Lee D, Jeon S, Park S et al. The feasibility of endoscopic submucosal dissection for rectal carcinoid tumors: comparison with endoscopic mucosal resection. Endoscopy 2010; 42: 647-651
• 4 Kumar AS, Sidani SM, Kolli K et al. Transanal endoscopic microsurgery for rectal carcinoids: the largest reported United States experience. Colorectal Dis 2012; 14: 562-566
• 5 Binmoeller KF, Weilert F, Shah J et al. “Underwater” EMR without submucosal injection for large sessile colorectal polyps (with video). Gastrointest Endosc 2012; 75: 1086-1091