Successful Endoscopic Resection of Large Pedunculated Brunner's Gland Hamartoma Causing Gastrointestinal Bleeding Arising from the Pylorus

Brunner's gland hamartoma is a rare benign small bowel neoplasm and most lesions are small and asymptomatic. However, large hamartoma-related obstructive symptoms and hemorrhage related to tumor ulceration manifest as hematemesis or melena. The exact pathogenesis if these lesions is not well known, but they are thought to be frequently associated with Helicobacter pylori infections and chronic pancreatitis. We report the case of a 45-year-old man who presented with melena due to a large pedunculated Brunner's gland hamartoma arising from the pylorus. It was successfully removed by endoscopic mucosal resection with piecemeal technique because of too large tumor size for application of a conventional snare.