抄録
We have presented here a case of atypical insulinoma. Despite the recurrent episodes of hypoglycemic symptoms, the plasma level of insulin has never been excessive at fasting or by regular provocative tests. Detailed examination had demonstrated qualitative rather than quantitative abnormality of insulin secretion. Hyposuppressibility of insulin secretion by hypoglycemia, borderline diabetic curveof glucose tolerance test, blunted response of insulin to glucagon and leucine were the principal characteristics of these abnormalities. After removal of adenoma, insulin response to glucose, glucagon and leucine was improved. Only secretin provoked a high level of insulin and this abnormal elevation was no longer seen after the removal of adenoma. A removed insulinoma contained 25 U of immunoreactive insulin per gram tissue, but was negative for aldehyde-fuchsin staining. On electronmicroscopy, only atypical β-cell granules were seen.
