The significance of gastrinomas found in peripancreatic lymph nodes. A patient with Zollinger-Ellison syndrome (ZES) was found to have a solitary, extrapancreatic, extraintestinal gastrinoma in a peripancreatic lymph node. Preoperative studies did not show the location of the tumor. After excision of the gastrinoma the patient's fasting serum gastrin level dropped from preoperative levels of 596 pg/ml to 120 pg/ml (normal, less than 200 pg/ml). Fasting and stimulated gastrin levels have remained within the normal range at 18 months follow-up. This patient had previously undergone antrectomy, so it could not be determined if this tumor represented a primary lymph node gastrinoma or metastasis from an unrecognized tumor that may have been present in the resected stomach or duodenum. The outcome of this case confirms the previous reports that ZES can be controlled after resection of gastrinomas that were contained within abdominal lymph nodes, even if a primary enteropancreatic tumor is not found. Our results also support the use of an aggressive operative search aimed at eradication of the tumor in patients with ZES even if preoperative localization studies fail to identify the site of the gastrinoma. 