Exploration of the Gastrinoma Triangle

Abstract

Zollinger and Ellison first described gastrin-secreting neoplasms in 1955. These unusual neoplasms are malignant. Diagnosis of the Zollinger-Ellison syndrome (ZES) depends on measurement of an increased fasting serum gastrin concentration (> 100 pg/mL), increased basal acid output (> 10 mEq/L, or > 5 mEq/L in patients with prior acid-reduction surgery), and an abnormal secretin test (increase of > 200 pg/mL in serum gastrin concentration after 2 U/kg of intravenous secretin).

Although gastrinomas originally were believed to be primarily neoplasms of the pancreas, today we know that most gastrinomas arise in the wall of the duodenum. Gastrinomas can occur as sporadic (nonfamilial) neoplasms or as one of the manifestations of multiple endocrine neoplasia type 1 (MEN1) syndrome; MEN1 includes pituitary neoplasms (most commonly prolactinomas), parathyroid hyperplasia, and neuroendocrine neoplasms of the duodenum and pancreas. In addition, patients with MEN1 may manifest benign thyroid neoplasms, benign and malignant adrenocortical neoplasms, lipomas, and cutaneous angiofibromas, as well as other neuroendocrine neoplasms of the foregut and midgut.

Most gastrinomas (especially the occult neoplasms) arise in the proximal duodenum, but gastrinomas also occur in the pancreas, especially in association with MEN syndrome. Sporadic gastrinomas are usually solitary, whereas gastrinomas associated with MEN1 are frequently multiple. Several ostensibly “primary” lymph node gastrinomas have been reported to occur within the gastrinoma triangle, with long-term cure after lymphadenectomy alone.