Endoscopic mucosal resection-assisted mucosal flap creation to facilitate endoscopic submucosal dissection for gastric adenoma amid diffuse fundic gland polyposis.

Background and Aims: Endoscopic submucosal dissection (ESD) for a gastric lesion in a patient with familial adenomatous polyposis (FAP) with fundic gland polyps is challenging due to dense polyposis, limiting visualization and access during resection. Methods: A 49-year-old woman with FAP and a high-grade dysplastic gastric lesion underwent ESD. Because of dense polyposis obscuring the instrument tip, proximal EMR was performed under saline solution immersion to create a submucosal entry point for the ESD. Results: The proximal EMR enabled clear visualization of the submucosal layer and facilitated safe initiation of ESD. After traction-assisted ESD, en bloc resection was achieved without adverse events. The post-ESD defect was successfully closed with endoscopic suturing. Follow-up upper endoscopy at 3 months showed no local recurrence. Conclusions: This case highlights the technical challenges of performing gastric ESD in patients with FAP and dense fundic gland polyps, in which visualization and access to the submucosal layer are limited. Creating a submucosal entry point with EMR can improve exposure and facilitate safe initiation of ESD. This hybrid approach may serve as a useful strategy for endoscopists facing similar difficult anatomy.