Localization of the source of hyperinsulinism: percutaneous transhepatic portal and pancreatic vein catheterization with hormone assay.

Insulin concentrations were measured in the portal venous system through the percutaneous transhepatic approach in 12 patients with organic hyperinsulinism. Single insulinomas were found in 10, an adenoma and islet cell hyperplasia in one, and nesidioblastosis in one patient. Angiography localized adenomas in two. Local step-ups of insulin levels in the portal venous system, found in all patients with insulinomas, corresponded to tumor sites at surgery. Multiple step-ups were found in the portal venous system of the patient with nesidioblastosis and the patient with an adenoma with islet cell hyperplasia. Three tumors were localized in the head of the pancreas which would indicate the primary surgical approach rather than blind resection of the body and tail. Three of the 10 adenomas were not identifiable by palpation after pancreatic mobilization during surgery. In all patients, organic hyperinsulinism was cured after surgery. Percutaneous transhepatic portal and pancreatic vein catheterization with measurement of radioimmunoactive insulin concentrations is a safe and reliable method and may play an important role in the localization of adenomas in patients with normal angiographic studies and previous negative surgical explorations.