A Case Report of Non-typical Annular Pancreas Diagnosed during Laparoscopic Gastric Surgery.

An annular pancreas is a rare anomaly of the pancreas, defined as pancreatic tissue that totally or partly encircles the duodenum, usually the descending portion. A 76-year-old man who was diagnosed with gastric cancer cT3N0M0 Stage IIB underwent laparoscopic distal gastrectomy with D2 lymph node dissection. Intraoperatively, the dorsal half of the duodenal bulb was seen to be half surrounded by the pancreas, and a non-typical annular pancreas was diagnosed. Because of the risk to the pancreas, it was considered impossible to perform anastomosis by a linear stapler as in the usual laparoscopic procedure. Therefore, we performed laparoscopically assisted distal gastrectomy and Billroth-I reconstruction using a circular stapler, and the surgery was completed without difficulties. His postoperative course was good despite the development of a pancreatic fistula, which was an International Study Group for Pancreas Fistula biochemical leak. Some APs can be diagnosed preoperatively, but the rarer subtypes such as ours are more difficult to visualize on imaging. In gastrectomy, it is both oncologically important and technically challenging to perform lymph node dissection around the pancreas. In this case with an especially proximal pancreas, a circular stapler was considered better suited for gastroduodenal anastomosis and required a broader field than that afforded by laparoscopy. A case of non-typical annular pancreas diagnosed during laparoscopic gastric surgery is described.