Localization of insulinomas and islet cell hyperplasias by pancreatic vein catheterization and insulin assay.

Percutaneous transhepatic portal vein catheterization and transfemoral portal and caval catheterizations were performed under local anesthesia in five patients with symptoms of organic hypoglycemia. During the investigation, results of pancreatic phlebography revealed the pancreatic venous anatomy. Blood obtained from the celiac artery, caval branches and pancreatic veins was assayed for insulin by two different radioimmunoassay methods. Pathologically high, pancreatic arteriovenous insulin differences in two patients with insulinomas and in two patients with islet cell hyperplasia. In one of the patients with an insulinoma, one of the assays failed to detect the tumor insulin. This inconsistency still remains unexplained. Angiography revealed a pancreatic abnormality in only two patients. During operation, two of the tumors were found upon palpation and inspection. Pancreatic resections were performed according to the findings of pathologic hormone differences in all five patients. Immunocytochemistry revealed that three of the patients had insulin-producing tumors and two had local islet cell hyperplasia. Catheterizations performed two months postoperatively confirmed the radicality of the operation in all patients, with the possible exception of one patient. In one patient, a recurrance was detected by catheterization ten months postoperatively.