Intraoperative endoscopic ultrasonography in Zollinger-Ellison syndrome.

In a 46-year-old man with Zollinger-Ellison syndrome, multiple imaging studies were negative for a primary gastrinoma. Preoperative endoscopic ultrasonography (EUS) revealed a 3.3-cm mass which appeared to be in the pancreatic head. During surgery, a celiac lymph node of the size of the mass seen by EUS was found, but the pancreatic head also felt firm and was suspicious for a mass. After resection of the celiac node, intraoperative EUS revealed no mass in the pancreatic head. Based upon intraoperative EUS findings, the pancreatic head was not resected. Histologic evidence of gastrinoma was found in the celiac lymph node and a 4 to 5 mm nodule in the duodenal wall. Postoperatively serum gastrin levels returned to normal.