Preferential localization of regional metastases from gastroenteropancreatic endocrine tumors with somatostatin-receptor scintigraphy.

Somatostatin-receptor imaging is an effective method for localizing and staging neuroendocrine tumors. We describe patients with gastroenteropancreatic endocrine tumors who underwent preoperative indium In 111 pentetreotide scintigraphy. In 3 patients without prior resections, the results of a 111In pentetreotide scan were positive because of unsuspected regional lymph node metastases without localization of the primary tumors. In these patients, an extensive intraoperative search was required to identify the primary tumors, despite the positive preoperative scan results. In a fourth patient, who had previously undergone resection of a duodenal gastrinoma, 2 regional nodal metastases were identified by a 111In pentetreotide scan.