A case of insulinoma identified by computed tomography and percutaneous transhepatic portal vein catheterization

A 50-year-old woman was admitted to hospital in May 1981 because of hypoglycemic episodes. Her fasting blood glucose, immunoreactive insulin and C-peptide immunoreactivity levels were 30 -- 55 mg/dl, 8 -- 20 μU/ml and 1.25 -- 2.13 ng/ml, respectively. Positive results were not obtained by provocative tests on insulin secretion (glucose tolerance, tolbutamide, leucine, glucagon and calcium infusion tests). Angiography of the celiac and superior mesenteric arteries, endoscopic retrograde pancreatography and ultrasonic examination of the pancreas, failed to reveal any tumor. Computed tomography demonstrated a slightly dense lesion measuring 1 cm in diameter in the tail of the pancreas. The insulin levels in the portal and splenic venous blood obtained by percutaneous transhepatic catheterization showed a prominent peak (58 μU/ml) in the splenic vein which suggested an insulin-secreting tumor in the tail. A tumor (1 x 1 x 0.7 cm) was subsequently found in the tail of the pancreas at operation. This study indicates that computed tomography and percutaneous transhepatic portal vein catheterization can be important in the preoperative localization of insulinoma. (author)