Endoscopic ultrasonography (EUS) in the localization of insulinoma

Objective Endoscopic ultrasonography has been accepted as a sensitive modality for preoperative tumor localization in pancreas. We have aimed to determine the performance characteristics of endoscopic ultrasonography in pancreatic insulinoma localization and evaluation of relationship between the tumor size and serum-c peptide level, lowest glucose level and insulin level. Methods Patients suspicious to insulinoma according to clinical and laboratory findings were included. Endoscopic ultrasonography was performed and if a tumor was identified, the patient was referred for surgery. Results A total of 52 patients (24 male and 28 female) with mean age of 42.4 years underwent EUS and 43 patients underwent surgery. In one patient, a tumor was identified both by transabdominal ultrasonography and abdominal CT scan. The overall sensitivity and accuracy of endoscopic ultrasonography for detection of insulinoma was 89.5% and 83.7% respectively. The sensitivity of endoscopic ultrasonography for detection of lesions in pancreatic head, body and tail was 92.6%, 78.9%, and 40.0%, respectively. There was no relationship between c-peptide, lowest blood glucose, insulin blood levels and tumor size in surgery. Conclusion EUS is an accurate method for detection of insulinoma. The accuracy depends on the location of the tumor and is greatest for tumors in the pancreatic head.