Abstract

An insulinoma is an endocrine tumor of the pancreas derived from the beta cells with abnormal insulin secretion. An insulinoma is rare, the incidence being estimated at only four per one million person-years. The association of diabetes mellitus and insulinoma is extraordinarily rare, but we should not overlook an insulinoma as a possible cause of hypoglycemia in patients with diabetes mellitus. A 70-year-old diabetic man who had been treated with oral hypoglycemic agents for type 2 diabetes suffered from night sweating for 10 days. Even after he stopped taking his oral hypoglycemic agents, the night sweating continued. The patient was admitted to evaluate the cause of the recurrent hypoglycemic events. After a 72-hour fasting test and selective arterial calcium stimulation test with venous sampling, he was diagnosed with insulinoma accompanied by type 2 diabetes mellitus. In the course of the study, the patient was also incidentally diagnosed with lung cancer.

• Keywords: Diabetes mellitus;Hypoglycemia;Insulinoma;