Localization of endocrine tumors of the pancreas with endoscopic ultrasonography.

High-frequency endoscopic ultrasonography (EUS) was used to image the pancreas through the wall of the stomach and duodenum in 12 patients with clinically suspected pancreatic endocrine tumors. In another patient, endocrine tumors in the wall of the duodenum were imaged by EUS. The findings were compared with those obtained by dynamic computed tomography (all patients) and selective angiography (eight patients). Laparotomy was done in eight patients. In our 13 patients, EUS detected endocrine tumors of the pancreas and duodenum in ten patients. More than one tumor was evident in five patients, including one of two patients with multiple endocrine neoplasia syndrome type I. In the eight patients treated surgically, there was one false-positive finding as a result of hypertrophic peripancreatic lymph nodes and one false-negative finding, in retrospect obviously imaged but incorrectly interpreted. The technique of EUS imaged small tumors in the pancreas (0.5 to 2.0 cm in diameter) in five patients where dynamic computed tomography and selective angiography were negative, but surgery and pathologic examination confirmed the EUS findings. This technique appears to be an important new addition to the battery of tests used for preoperative localization of endocrine tumors of the pancreas.