Gastrinoma, underlying Zollinger-Ellison syndrome, is a pancreatic islet cell tumor within endocrine pathology in which ectopic malignant cells (typically in the pancreas, duodenum, or peripancreatic "gastrinoma triangle") secrete gastrin outside its normal site of production (G cells of the gastric antrum). The core mechanism is that circulating gastrin excessively stimulates parietal cell hydrochloric acid secretion via the gastrin/CCK-B receptor complex, producing a pathologic excess of acid delivered into the duodenum and beyond. This mechanism explains the syndrome's characteristic findings—recurrent, refractory peptic ulceration that can extend atypically into the jejunum, along with malabsorption and diarrhea from acid-mediated mucosal and digestive disruption—illustrating how ectopic hormone-secreting tumors of the endocrine pancreas produce disease through excessive normal physiological signaling in an abnormal anatomic or quantitative context.
Gastrinoma, underlying Zollinger-Ellison syndrome, is a pancreatic islet cell tumor within endocrine pathology in which ectopic malignant cells (typically in the pancreas, duodenum, or peripancreatic…