ADENOMA OF PANCREATIC ISLET CELLS WITH HYPOGLYCEMIA AND HYPERINSULINISM: Report of a Case with Studies on Blood Sugar and Metabolism before and after Operative Removal of Tumor.

Shortly after Banting and Best's discovery of insulin (1), Harris (10) in 1924, on the basis of cases of hypoglycemia with symptoms similar to those of insulin shock and relievable by feeding, postulated the occurrence of spontaneous " hyperinsulinism " as opposed to the " hypoinsulinism " of diabetes. The first verification of this hypothesis appeared in 1927 in a report by Wilder, Allan, Power and Robertson (26) of a case of intractable hypoglycemia. The patient, on exploration, showed carcinoma of the islet tissue of the pancreas with metastasis to the liver. Insulin was demonstrated in the hepatic metastases. Two years later Howland, Campbell, Maltby and Robinson (12) reported the first case of pancreatic islet adenoma which was diagnosed preoperatively, identified at operation and excised with favorable result. In the past few years the literature on hyperinsulinism has grown tremendously. A review by Whipple and Frantz (25) of all the published cases of hyperinsulinism and islet tumor has appeared very recently. According to their analysis of the 157 cases reported, 75 cases of hypoglycemia were ascribed to hyperinsulinism without verification at operation or autopsy. Of the 82 remaining cases in which the pancreas was examined, normal tissue was recorded in 13 instances, hypertrophy of the islands in 4 instances and chronic inflammatory change in 3, leaving 62 instances in which a tumor of the pancreatic islands was found. Analyzing further the 62 cases of tumor, exactly 50 per cent were incidental necropsy findings without recorded hypoglycemia. The group of 31 cases of tumor associated with hypoglycemia consists of 10 discovered at autopsy and 21 at operation. Among the last 21 cases, 4 were instances of carcinoma in which death occurred shortly after operation in 2 instances. There remain 17 patients with adenoma, the excision of which led to eventual recovery. Thus in spite of frequent reports of hypoglycemia and hyperinsulinism, adenoma of the pancreatic islets, verified at operation with favorable outcome after extirpation of the tumor is a relatively rare condition. We are reporting the history of such a case together with the results of blood sugar and metabolism studies and biological assay of the tumor for insulin.