The gastrinoma syndrome, or Zollinger-Ellison syndrome, has traditionally been associated with a severe, fulminant ulcer diathesis, often with multiple ulcers, and ulcers in unusual locations such as the post-bulbar region of the duodenum and proximal jejunum. However, with increasing recognition of this syndrome, as well as the availability of a radioimmunoassay for serum gastrin, most patient's with gastrinoma now present with either milder forms of peptic ulcer disease, or with secretory diarrhea. The syndrome can exist in multiple forms, including benign sporadic, malignant metastatic, and as part of the MEN-I syndrome. Approximately 66% of gastrinomas are sporadic[1]. Sporadic tumors are reported to be malignant in approximately 40-85% of cases. Sporadic gastrinomas occur primarily in the gastrinoma triangle, defined as the confluence of the cystic and common bile duct superiorly, the second and third portions of the duodenum inferiorly, and the neck and body of the pancreas medially.[2] Although they can occur in the pancreas, the duodenum has been shown to be the most common site of gastrinomas, based on the pioneering work of Debas and colleagues[3], Thompson and colleagues[4], and others. Duodenal wall gastrinomas have been identified in 43-77% of patients[4-6]. These duodenal wall tumors are frequently small and multiple. Sporadic tumors occurring in the pancreas tend to be solitary. Primary tumors may also occur in a variety of ectopic sites, including the body of the stomach, jejunum, peripancreatic lymph nodes, splenic hilum, root of the mesentery, omentum, liver, gallbladder, common bile duct, and the ovary[1, 7-13]. A recent immunohistochemical study in 20 autopsy patients suggests that primary lymph node gastrinomas are due to entrapment of neuroendocrine cells during development.[14] Overall, about 5.6% of patients have a primary gastrinoma located in an ectopic site[15]. Another study suggests that up to 10% of sporadic gastrinomas are lymph node primaries [16]. Solitary tumors in ectopic sites are less likely to be malignant than solitary tumors in pancreatic sites [13]. Although traditionally surgical cure rates have been less than 50%, the increasing recognition of the duodenal wall as the most common location of gastrinoma has resulted in an increasing number of surgical cures.