Endoscopic full-thickness resection and submucosal tunneling endoscopic resection: Strategies for resecting subepithelial lesions

Subepithelial lesions of the gastrointestinal tract are masses with an overlying layer of normal mucosa, most frequently found in the stomach and often detected incidentally. They may originate from the submucosa, muscularis mucosa, or muscularis propria and encompass a broad differential diagnosis. Endoscopic ultrasound provides important diagnostic information and lesion characterization, enabling risk stratification and guiding the selection of resection technique where indicated. Management is determined by malignancy risk, lesion size, and patient-specific factors. While observation is appropriate in many asymptomatic cases involving small lesions, resection is indicated for larger lesions (> 2 cm), symptomatic cases, inconclusive pathology results, and/or when the presence of a lesion confers significant psychological or financial burden to the patient. Recent advancements in endoscopic resection techniques have expanded treatment options beyond surgery, enabling minimally invasive and organ-sparing approaches. Techniques include endoscopic submucosal resection with cap- or ligation-assisted resection and underwater endoscopic mucosal resection for lesions primarily involving the submucosa. Larger or deeper lesions are addressed through endoscopic full-thickness resection, which can be categorized into exposed and nonexposed methods. Each has technical considerations, including closure strategies, size limitations, and complication risks. Exposed endoscopic full-thickness resection offers high en bloc resection rates but carries a risk of perforation, whereas nonexposed tunneling techniques are preferred in anatomically challenging regions such as the esophagus. Device-assisted resection using full-thickness resection devices presents a promising “one-stop” solution for selected subepithelial lesions but may be limited by lesion size and device constraints. Optimal management requires a multidisciplinary, patient-centered approach informed by lesion characteristics, advanced resection expertise, and the available technology.