Endoscopic ultrasound is highly accurate and directs management in patients with neuroendocrine tumors of the pancreas

OBJECTIVE: Preoperative localization of pancreatic neuroendocrine tumors wi th traditional imaging fails in 40-60% of patients. Endoscopic ultrasound ( EUS) is highly sensitive in the detection of these tumors. Previous reports included relatively few patients or required the collaboration of multiple centers. We report the results of EUS evaluation of 82 patients with pancr eatic neuroendocrine tumors. METHODS: We prospectively used EUS early in the diagnostic evaluation of pa tients with biochemical or clinical evidence of neuroendocrine tumors. Pati ents had surgical confirmation of tumor localization or clinical follow-up of >1 yr. RESULTS: Eighty-two patients underwent 91 examinations (cases). Thirty pati ents had multiple endocrine neoplasia syndrome type I. One hundred pancreat ic tumors were visualized by EUS in 54 different patients. The remaining 28 patients had no pancreatic tumor or an extrapancreatic tumor. Surgical/pat hological confirmation was obtained in 75 patients. The mean tumor diameter was 1.51 cm and 71% of the tumors were less than or equal to 2.0 cm in dia meter. Of the 54 explorations with surgical confirmation of a pancreatic tu mor, EUS correctly localized the tumor in 50 patients (93%). Twenty-nine in sulinomas, 18 gastrinomas, as well as one glucagonoma, one carcinoid tumor, and one somatostatinoma were localized. The most common site for tumor loc alization was the pancreatic head (46 patients). Most tumors were hypoechoi c, homogenous, and had distinct margins. EUS of the pancreas was correctly negative in 20 of 21 patients (specificity, 95%). EUS was more accurate tha n angiography with or without stimulation testing (secretin for gastrinoma, calcium for insulinoma), transcutaneous ultrasound, and CT in those patien ts undergoing further imaging procedures. EUS was not reliable in localizin g extrapancreatic tumors. CONCLUSIONS: In this series, the largest single center experience reported to date, EUS had an overall sensitivity and accuracy of 93% for pancreatic neuroendocrine tumors. Our results support the use of EUS as a primary diag nostic modality in the evaluation and management of patients with neuroendo crine tumors of the pancreas. (Am J Gastroenterol 2000;95:2271-2277. (C) 20 00 by Am. Coll. of Gastroenterology).