The present paper reports 2 cases of insulinoma. Thr first case was a 14-yr-old junior high school girl. She was admitted to hospital due to increasing frequency of hypoglycemic episodes which were induced by intensive physical exercise or prolonged fasting.
The second case was a 63-yr-old man who suffered from general weakness, dizziness and unconciousness in the fasting state. He was recommended by a psychiatrist to undergo clinical and endocrinological examinations.
The diagnosis of a functioning islet-tumor was made in the first case on the basis of excessive insulin secretion in the fasting state and in response to various physiological or pharmacological stimuli. Selective celiac angiographical examinations revealed a tumor at the tail of the pancreas.
However, in the second case, after various laboratory tests and procedures the only typical findings of insulinoma were inappropriate values of plasma immunoreactive insulin in relation to the corresponding values of blood glucose, and these were sporadic. Fractionation of fasting serum samples by Bio-Gel P-30 column chromatography revealed large amounts of proinsulin-like component. Selective celiac angiography yielded no evidence of a tumor. During the period before a surgical operation was performed, a regimen of β-blocker was effective in abolishing his symptoms of hypoglycemia.
Microscopical diagnosis revealed a benign adenoma in both cases. The recoveries from surgery were uneventful and the patients have remained free of symptoms for several years.