Abstract We report a 20-year-old female with a gastric submucosal tumor at the upper body greater curvature, successfully managed by endoscopic full-thickness resection (EFTR) using a modified traction-assisted purse-string suture. The 4.0-cm wall defect was closed in 34 min (total procedure 108 min). Pathology revealed 23 IgG4 + plasma cells/HPF, an IgG4/IgG ratio of 48%, and storiform fibrosis, meeting diagnostic criteria for IgG4-related inflammatory pseudotumor (IPT).