title: Concurrent insulinoma and impaired glucose tolerance suspected as owing to obesity.
abstract: An obese 68-year-old woman was admitted for examination of fasting hypoglycaemia. A prolonged 18 h fast reduced her plasma glucose without suppressing insulin secretion, while plasma β-hydroxybutyrate levels were suppressed. Despite the prolonged fast, the glucose response to glucagon was increased by 25 mg/dL (1.39 mM) glucose, which is compatible with insulinoma. A 75 g oral glucose tolerance test (75 g OGTT) showed impaired glucose tolerance. An abdominal CT scan revealed a mass lesion in the uncinate process of the pancreas, a finding consistent with the results of angiography and selective artery calcium injection test. The patient then underwent a pancreaticoduodenectomy; the pancreatic mass was histologically diagnosed as benign insulinoma. After surgery, a prolonged 24 h fast caused no hypoglycaemia and the glucose tolerance capacity in 75 g OGTT improved. Eight months after surgery, the patient's body weight had reduced by 10 kg. This is therefore a case of concurrent insulinoma and impaired glucose tolerance.
authors.affiliation: Diabetes and Endocrinology, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Iizuka
authors.affiliation: Diabetes and Endocrinology, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Fujisawa
authors.affiliation: Diabetes and Endocrinology, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Takeda
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007003:Hypoglycemia; D007328:Insulin / Q000097:blood*; D007340:Insulinoma / Q000097:blood / Q000175:diagnosis*; D009765:Obesity / Q000150:complications*; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D016577:Pancreaticoduodenectomy
chemical_list: D001786:Blood Glucose; D007328:Insulin