A Case Report of Hyperinsulinism

Abstract

Recently we experienced one patient of the islet cell tumor who was frequently attacked with a typical hypoglycemia. We measured the blood glucose level and found it was severely hypoglycemic. The fasting test was positive and a long duration of severe hypoglycemia was observed on the tolbutamide test.
We also determined the serum insulin-like activity in this patient by the method with the hypophysectomized-adrenolectomized rats, that was 8.6 mu/ml and twice higher than that of normal.
After tolbutamide was injected intravenously, the insulin-like activity elevated to 21.0 mu/ml. This prominent elevation may be considered to be specific for insuloma. From these data we diagnosed his disease as insuloma.
On laparotomy we resected a tumor in size of the first finger from the head part of his pancreas. On the histological examination, it was found to be a benign islet cell adenoma in which the content of zinc and β-granules decreased.
The amount of insulin in this tumor was 4.89u/g and it was twice higher than that of normal. The decrease of β-granules in the tumor does not coincide with the amount of insulin, but this may be due to the specificity of this kind of tumor.
After the operation, the patient has never suffered from the seizure of hypoglycemia.