AN INTRACTABLE CASE OF INSULINOMA
We had experienced an intractable case of insulinoma to diagnose and treat. A 53-year-old. obese woman had suffered unconsciousness on excercise as hypoglycemic attack about once a month for 5 years. The oral glucose tolerance test, glucagon test, tolbutamide test, 1-leucine test and bonito insulin suppression test showed abnormalities not in insulin but in plasma blood sugar level (hypoglycemia). Fasting hypoglycemia and positive sign of fasting test for 43.5 hours were obtained. Glucose-tolbutamide-glucagon test elevate serum insulin level from 9 to 289 μU/ml. Absence of insulin release in response to calcium was obtained in the patient. A tumor stain (about 1.1 cm in diameter) was revealed at the tail of the pancreas by coeliacography, but computerized tomography was of little value in this case. A solitary adenoma (1.5 x 1.3 x 1.1 cm, about 1 g) was removed surgically. The histological findings were B-cell adenoma of type IV with amyloid deposition. After surgery, hypoglycemic episodes disappeared completely.