Metabolic studies in a child with a pancreatic insulinoma.

An 8-year-old boy with a convulsive disorder for 3 1/2 years remined seizure free for 20 months while being treated with phenytoin (diphenylhydantoin) sodium, and then he had a relapse. He first demonstrated hypoglycemia when he fasted prior to being placed on a ketogenic diet. An oral glucose tolerance test indicated fasting and postglucose hypoglycemia and substantial hyperinsulinemia. Somatostatin infusion resulted in a modest increase in plasma glucose levels and a decrease in serum insulin concentrations. A discrete pancreatic mass was demonstrated preoperatively by celiac angiography that on surgical extirpation, proved to be a benign intrapancreatic insulinoma. Evaluation for islet cell tumors is of importance in children with seizure disorders unresponsive to anticonvulsant medication. Furthermore, somatostatin may be useful preoperatively in maintaining normal blood glucose concentrations in patients with islet cell adenomas.