Treatment of hyperinsulinemic hypoglycemia due to diffuse nesidioblastosis in adults: a case report

An 82-year-old man was admitted to our hospital with a complaint of hypoglycemic syncope in the early morning. Insulinoma was suspected, but an abdominal CT showed no mass. Abdominal angiography showed a slight stain fed from the splenic artery. Arterial stimulation and venous sampling (ASVS) showed an abnormal insulin response only from the splenic artery. Under a provisional diagnosis of insulinoma, surgical treatment was undertaken. Although no pancreatic masses were palpable, we performed a distal pancreatectomy. Subsequently, a pathological examination revealed diffuse nesidioblastosis. Reported cases of diffuse nesidioblastosis have had common clinical features: postprandial hyperinsulinemic hypoglycemia, no abnormal findings in radiological examinations, and the presence of the ductulo-insular complex on histological examination. Surgical resection is recommended, but the extent of surgery is controversial. Our case had some clinical features of insulinoma but was diagnosed as diffuse nesidioblastosis according to histopathologic criteria. Because ASVS showed that the pancreatic body and tail had a lesion producing insulin abnormally, we performed a distal pancreatectomy to cure the hypoglycemia. Clinically, it is very difficult to distinguish diffuse nesidioblastosis from insulinoma. When we treat hyperinsulinemic hypoglycemia, ASVS can be an essential examination to decide the extent of pancreatectomy.