Preoperative detection of duodenal gastrinomas and peripancreatic lymph nodes by somatostatin receptor scintigraphy

Background & Aims: Duodenal gastrinomas and peripancreatic lymph nodes are difficult to localize. The aim of this study was to evaluate the ability of Octreoscan scintigraphy to detect such tumors. Methods: Results of Octreoscan scintigraphy in 21 consecutive patients with Zollinger-Ellison syndrome were compared with those of conventional imaging techniques, including endoscopic ultrasonography, and with the surgical findings. Results: Surgical exploration found 27 duodenal and/or lymph node gastrinomas in 19 patients. None had pancreatic gastrinoma. Octreoscan scintigraphy was the only positive preoperative technique in 32% of the patients. The sensitivities of conventional techniques, Octreoscan scintigraphy, and their association were 58%, 58%, and 90%, respectively, for all resected gastrinomas. The smallest duodenal gastrinoma detected by Octreoscan scintigraphy measured 3 mm. Endoscopic ultrasonography detected all the tumors visualized by any other conventional technique and was considered falsely positive, as was Octreoscan scintigraphy, in 1 patient. Follow-up and comparison between the number of resected gastrinomas and the number of preoperative hot spots suggested that surgeons should find at least as many tumors as the number of hot spots. Conclusions: Octreoscan scintigraphy improved the preoperative detection of extrapancreatic gastrinomas, mainly by endoscopic ultrasonography. Surgeons should find at least as many gastrinomas as the number of hot spots.