A 15-year-old boy accidentally ingested a mouthful of sulfuric acid (160g/L). He presented 20 days later with complaints of postprandial epigastric distress, repeated nonbilious vomiting, and marked weight loss (about 15kg). Barium swallow and endoscopy revealed antropyloric narrowing (●" Fig.1,●" Fig.2). Endoscopic balloon dilation was performed, and the symptoms were relieved. However, 2 mont...