NESIDIOBLASTOSIS IN AN ADULT WITH HYPERINSULINEMIC HYPOGLYCEMIA

A 50-year-old Korean man with repeated episodes of temporary loss of c onsciousness was diagnosed as having hyperinsulinemic hypoglycemia. Un der the tentative diagnosis of insulinoma, localization procedures wer e carried out but no tumor was found. By percutaneous transhepatic por tal venous sampling, no definite gradient in insulin concentration was found. During exploratory laparotomy no tumor was palpable in the pan creas, and intraoperative ultrasonography showed low echogenicity in t he pancreatic head. Whipple's operation was performed and 70% of the p roximal pancreas was removed. Histomorphometric examination of the res ected specimen revealed graded hyperplasia of the islet cells. The mos t profuse hyperplasia was noted in the head with progressive decrease in the degree of hyperplasia to the body and tail. The patient remains euglycemic and tolerates 24 h fasting without any medication until 15 months after operation.