Simple water infusion via a non-traumatic tube facilitates endoscopic resection of an appendiceal-orifice polyp

We present the case of a 53-year-old man who was referred after fecal immunochemical test-positive colonoscopy revealing a polyp in the appendiceal orifice (AO). In our initial examination, the polyp could not be visualized with air insufflation or water immersion ([Fig. 1]), even with traction using biopsy forceps. A repeat colonoscopy 3 months later failed to expose the lesion, even with traction using a multi-loop traction device (Boston Scientific Co. Ltd, Tokyo, Japan). Subsequently, a non-traumatic tube was carefully inserted into the appendiceal lumen ([Fig. 2]). Continuous water infusion through the tube generated hydraulic pressure that extruded the polyp into the cecal lumen, thus permitting stable visualization ([Fig. 3]). The lesion appeared pedunculated with a 10-mm head. Magnifying narrow band imaging revealed Japan NBI Expert Team classification Type 2A, consistent with adenoma. After placement of a hemostatic clip at the stalk base, en bloc resection was performed using underwater endoscopic mucosal resection. Complete resection was confirmed endoscopically and additional prophylactic clips were applied ([Fig. 4]). The procedure was completed without any adverse events. Histopathological examination revealed a tubular adenoma with negative margins ([Fig. 5]).

Fig. 1 The lesion could not be visualized with water immersion.

Fig. 2 A non-traumatic tube was inserted into the appendiceal lumen.

Fig. 3 Continuous water infusion through the tube generated hydraulic pressure that extruded the polyp into the cecal lumen.

Fig. 4 Complete resection was confirmed endoscopically. The arrowhead indicates the edge of the resection base.

Fig. 5 Histopathology revealed tubular adenoma.

Polyps at the AO often require surgery because of difficulties in visualization and access [1]. To the best of our knowledge, this is the first report of targeted water infusion into the appendix via a non-traumatic tube to expose an AO polyp and enable safe resection using standard tools ([Video 1]). The safety of appendiceal intubation and irrigation is supported by reports of endoscopic retrograde appendicitis therapy [2] [3]. This simple and reproducible maneuver may expand endoscopic options and help avoid surgery for AO polyps.

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Simple water infusion via a non-traumatic tube facilitates endoscopic resection of an appendiceal-orifice polyp.Video 1

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Contributorsʼ Statement

Hajime Yoshii: Writing – original draft. Kazunori Takada: Supervision, Writing – review & editing. Kenichiro Imai: Supervision. Sayo Ito: Supervision. Kinichi Hotta: Supervision. Hiroyuki Ono: Supervision.

Conflict of Interest

The authors declare that they have no conflict of interest.

Acknowledgement

We would like to thank Editage (www.editage.jp) for English language editing.

• References

• 1 Kurokawa T, Kanemoto Y, Azuma Y. et al. Endoscopically unobservable appendiceal adenoma treated using laparoscopically assisted surgery: A case report. Int J Surg Case Rep 2021; 83: 105949
• 2 Xu Z, Jin L, Wu W. Clinical efficacy and safety of endoscopic retrograde appendicitis treatment for acute appendicitis: A systematic review and meta-analysis. Clin Res Hepatol Gastroenterol 2023; 47: 102241
• 3 Li Z, Chen Y, Zhang X. et al. Feasibility and effectiveness of endoscopic retrograde appendicitis therapy for uncomplicated acute appendicitis: a systematic review and meta-analysis. Surg Endosc 2025; 39: 4137-4145

Publication History

Article published online:
13 January 2026