Abstract: | We present the case of a 46‐year‐old obese woman with a 3.5‐cm adenoma in the descending part of the duodenum who was treated with a totally laparoscopic approach. The preoperative examination revealed a pedunculated superficial tumor on the side of pancreas from the inferior duodenal angulus to 5 cm proximal to the papilla that was associated with massive blood flow. We chose not to perform endoscopic submucosal dissection, pancreaticoduodenectomy, or transduodenal tumor excision with laparotomy for this obese patient because of the poor exposure, risk of bleeding, and substantial invasiveness. We performed endoscopy‐assisted laparoscopic submucosal dissection as a novel laparoscopic‐endoscopic cooperative surgical approach in this patient. This surgery was surgically and oncologically safe. |