title: Insulinoma: clinical and diagnostic features of 60 consecutive cases.
abstract: Insulinoma is a rare tumor, occurring more often in women and in the older age range. Eighty percent of patients have a single benign tumor, usually less than or equal to 2 cm in diameter, located with about equal frequency in body, head, or tail of the pancreas and amenable to surgical cure. About 10% have multiple tumors; in this group there is a high incidence of multiple endocrine neoplasia type I syndrome. The remaining 10% of patients have metastatic malignant insulinoma. Symptoms are intermittent, recur at irregular intervals in the food-deprived state over a median of 1 1/2 years, and arise from varying degrees of neuroglycopenia. Symptoms often lead to misdiagnosis as a neurologic or psychiatric disorder. Transient neurologic deficits and EEG abnormalities can be observed during hypoglycemia. Diagnosis requires repeated demonstration of hypoglycemia (glucose less than or equal to 40 mg/dl) during spontaneous or provoked symptoms, relief with ingestion of carbohydrates, simultaneous hyperinsulinemia (serum insulin greater than 6 muU/ml), and absence of insulin antibodies. A useful diagnostic adjunct is the intravenous tolbutamide test, for which new diagnostic criteria are presented.
mesh_terms: D007516:Adenoma, Islet Cell / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D003951:Diagnostic Errors; D004569:Electroencephalography; D005260:Female; D005951:Glucose Tolerance Test; D006729:Hormones, Ectopic / Q000097:blood; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000175:diagnosis; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009461:Neurologic Manifestations; D010180:Pancreatectomy; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D014044:Tolbutamide
chemical_list: D001786:Blood Glucose; D006729:Hormones, Ectopic; D007328:Insulin; D014044:Tolbutamide