Endocrine Abstracts

Background: Although very rare, insulinomas are the most commonly occurring endocrine tumor of the pancreas. The aim of this study was to review the clinical presentation, diagnostic approach and management of patients with an insulinoma.

Methods: 22 insulinoma patients, with an age range of 20–79, were included and evaluated according to their clinical presentation, blood biochemistry, imaging studies, operative management, pathological manifestations, postoperative and follow-up outcomes.

Results: The majority of the patients were female (65.2%) with a mean age of 53.0±18.8 years at the time of diagnosis. Their routinely measured mean morning fasting blood glucose levels were 72.4±18.3 mg/dl and only six patients had low blood glucose levels < 60 mg/dl. Their fasting blood insulin level and C-peptide levels were all in normal ranges. All the patients were admitted to the medical center and underwent 72 h supervised fast. Diagnosis of insulinoma was determined in 22 patients (female/male=14/8) by hyperinsuliemia during hypoglycemic episode and was assured in 21 patients with histological investigation after operation. A pancreatic mass was observed on transabdominal ultrasonography (US) or computerized tomography (CT) in 18 of the 22 (81.8%) patients preoperatively. Enucleation was performed in 17 patients (81.0%) if the lesion is clearly localized and small. Distal pancreatic resection was needed in the rest of four patients. Postoperative complications such as postoperative cyst and intra-abdominal infection were observed in six patients.

Conclusion: A high serum insulin level during hypoglycemic episode is highly specific for diagnosing insulinoma and US and CT appears to be a substantially useful preoperative investigation procedure for localizing a pancreatic adenoma. In unexperienced hands, intraoperative ultrasonography is not highly conclusive procedure for pancreatic tumor localization.