Endocrine pancreas neoplasia. Zollinger-Ellison syndrome
Pancreatic neuroendocrine tumours (PanNETs) are rare, they can be single or multifocal and when malignant they are most likely to metastasize to the liver. Generally these tumours produce insulin, but some are nonfunctional. Symptoms stem from overproduction of insulin (causing hypoglycemia - remember, insulin triggers uptake of glucose into the cell meaning there is less glucose in the blood). The genes responsible for PanNETs are MEN1, PTEN, TSC2, ATRX and DAXX.
Insulinomas are the most common pancreatic neuroendocrine tumour, these are beta cell tumours. The clinical picture is that of hypoglycemic attacks, causing confusion, stupor and loss of consciousness. Most are cured with surgical resection. Most insulinomas are not malignant, and look remarkably like giant islets with normal cellular preservation. Deposition of amyloid in the extracellular tissue is a characteristic feature under microscope.
H&E: pancreatic neuroendocrine tumour (top) - nests and trabeculae of uniform cells with round nuclei in a delicate vascular stroma; normal acinar pancreas below.
Image: “Pancreatic neuroendocrine tumour -- intermed mag” by Nephron, CC BY-SA 4.0, via Wikimedia Commons.
Remember: Whipple's triad points to an insulinoma: symptoms of hypoglycaemia, a low blood glucose measured during the attack, and relief of symptoms when glucose is given.
Zollinger-Ellison Syndrome
This is a syndrome caused by a gastrinoma, a tumour in the pancreas or duodenum causing excess secretion of gastrin which in turn leads to ulceration of the duodenum, stomach and the rest of the small intestine. Over half of gastrinomas are locally invasive or have metastasized at the time of diagnosis, and they often occur with other endocrine tumours. Patients with persistent duodenal and gastric ulceration who do not respond to standard therapy, should be considered possible sufferers of Zollinger-Ellison syndrome.
Memory aid: about a quarter of gastrinomas occur in MEN1, the "3 Ps": Parathyroid hyperplasia/adenoma, Pancreatic (and duodenal) neuroendocrine tumours, Pituitary adenoma.