Surgical treatment of insulinomas.

Differential diagnosis of hypoglycemic patients should include insulinoma. Plasma insulin-to-glucose ratio greater than 0.3 or C-peptide levels of 2 nmol/L or greater suggest insulinoma. Abdominal CT scan can exclude metastatic disease and identify uncommonly large islet cell tumors, but has poor sensitivity for localizing insulinomas; transgastric endoscopic ultrasound is the most sensitive technique. Palpation combined with intraoperative ultrasound identifies most tumors at operation and gives vital information about surrounding structures. If no tumor is found, blind distal pancreatectomy should not be performed, and the patient should be referred to an endocrinologist or endocrine surgeon for diagnostic confirmation and further localization. Laparoscopy is a viable alternative to open tumor resection; laparoscopic ultrasound can facilitate localization and guide safe resection.