Preoperative localization of pancreatic insulinoma by selective intraarterial calcium injection and hepatic venous sampling

Preoperative localization of insulinomas is desirable by most surgeons. Imaging with ultrasonography, computed tomography, magnetic resonance imaging, nuclear medicine and angiography may fail to demonstrate these small tumors in up to 10%, while a smaller percentage may be missed even after careful surgical exploration and intraoperative ultrasonography. Selective intraarterial injection of calcium with hepatic venous sampling has been reported to be a very accurate technique for preoperative localization of insulinomas. We report such a case where the clinical symptoms were highly suggestive but imaging algorithm failed to reveal any lesion and we review the literature.