Endoscopic ultrasound localization of a pancreatic insulinoma: case report and review of the localization techniques.

A 23-year-old male was referred to our hospital for evaluation of new-onset seizures. Signs and symptoms of neuroglycopenia, including weakness, dizziness, and confusion, appeared during fasting and resolved promptly with intravenous dextrose administration. Insulin, proinsulin, and C-peptide levels were consistent with a diagnosis of insulinoma. Screening tests for multiple endocrine neoplasia type 1 and surreptitious sulfonylurea uses were negative. Preoperative localization of the insulinoma by transabdominal ultrasonography, computed tomography, and indium-111 octreoscanning were unsuccessful. Endoscopic ultrasonography (EUS) identified a 6- to 7-mm tumor at the juncture of the head and body of the pancreas. Surgical exploration confirmed the preoperative localization, and an 8-mm tumor was simply enucleated. The patient has been free of symptoms for 18 months since surgery. This report describes the utility of EUS to localize a solitary pancreatic insulinoma and provides a comparison of EUS and other preoperative localization techniques.