J Korean Soc Endocrinol.
1995 Dec;10(4):434-438.
A Case of Insulinoma without Peripheral Hyperinsulinemia
Abstract
- Insulinoma is a disorder characterized by hypoglycemia due to endogenous hyperinsulinemia. The elevated plasma insulin level and hypoglycemia should be established for the diagnosis of an insulinoma. Other laboratory methods such as immunoreactive insulin to glucose(IRI/G) ratio, C-peptide, proinsulin, and some provocation tests are also employed to detect an insulinoma because hyperinsulinemia is often not found. Especially, IRI/G ratio has been considered as very sensitive and specific test to confirm the insulinoma without peripheral hyperinsulinemia. We report a case of insulinoma without hyperinsulinemia and elevation of IRI/G ratio, which was diagnosed by endoscopic ultrasonography and THPVS(Transhepatic portal venous sampling). It is suggested that more confirmatory tests will be necessary for the diagnosis of insulinoma especially when it is highly suspected although IRI/G ratio is not increased.