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. Download Video Simple water infusion via a non-traumatic tube facilitates endoscopic resection of an appendiceal-orifice polyp.Video 1 Endoscopy_UCTN_Code_TTT_1AQ_2AD_3AB Publication History Article published online: 13 January 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany