A novel application of the submucosal tunnel technique for resection of a giant duodenal lipoma

A 47-year-old male was admitted for investigation of melena. Esophagogastroduodenoscopy revealed a large, smooth, submucosal mass in the descending duodenum ([Fig. 1] a). The patient underwent endoscopic ultrasound and abdominal magnetic resonance imaging (MRI) for further characterization of the duodenal mass. Both studies were unequivocally consistent with a submucosal lipoma ([Fig. 1] b). The lesion was estimated to be >5 cm in the greatest diameter.

Fig. 1 Endoscopic resection of a giant duodenal lipoma using a submucosal tunnel technique. a Endoscopic view of the large, submucosal mass in the descending duodenum. b Axial abdominal MRI findings of the duodenal lipoma. c A horizontal mucosal incision was made at the proximal edge of the tumor. d Submucosal dissection was performed, creating a tunnel above the yellow fatty tissue of the lipoma. e The tumor was gradually extruded into the lumen. f The mucosal entry site was closed with endoclips and secured with a nylon loop.

Given the symptomatic nature of the lesion, endoscopic resection was indicated. Prior to dissection, we introduced a side-viewing duodenoscope to repeatedly verify that the lesion was unrelated to the papilla.

However, due to its enormous size and broad base, a standard ESD was deemed high-risk, as the resulting defect would be massive and impossible to close securely, posing a significant risk of perforation. We here presented a novel application of submucosal tunnel resection, allowing for en-bloc removal while preserving the overlying mucosa. The steps were as follows ([Video 1], [Fig. 1]): First, a 3-cm horizontal mucosal incision was made at the oral (proximal) edge of the tumor following submucosal injection ([Fig. 1] c). Then, the submucosal layer was dissected carefully above the tumor capsule to create a tunnel and the dissection was advanced distally between the mucosal layer and the tumor mass ([Fig. 1] d). As dissection proceeded, the tumor was gradually extruded into the lumen ([Fig. 1] e). Next, the final connection was cut, and the tumor was immediately captured and retrieved en-bloc with a snare. Finally, the mucosal incision site and the small residual defect were closed with endoclips and finally secured with a nylon loop ([Fig. 1] f). The resected specimen measured 7.0 cm × 4.0 cm ([Fig. 2]).

Download Video

The process of endoscopic resection of a giant duodenal lipoma.Video 1

Fig. 2 The resected lipoma specimen measuring 7.0 cm × 4.0 cm.

The patient recovered uneventfully, was started on a clear liquid diet on postoperative day 2, and was discharged on day 4. Pathological examination confirmed the diagnosis of a lipoma.

To our knowledge, this is the first report of a submucosal tunnel technique being used for a large duodenal lesion. It represents a valuable addition to the therapeutic endoscopist's arsenal for managing complex SMTs in this challenging anatomical location.

Endoscopy_UCTN_Code_TTT_1AO_2AG_3AZ

Contributorsʼ Statement

Jingjing Lian: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Writing – original draft. Aiping Xu: Investigation, Methodology, Writing – review & editing. Tao Chen: Data curation, Funding acquisition, Writing – review & editing. Meidong Xu: Investigation, Resources, Supervision.

Conflict of Interest

The authors declare that they have no conflict of interest.

Publication History

Article published online:
22 January 2026