EUS detection of pancreatic endocrine tumors in asymptomatic patients with type 1 multiple endocrine neoplasia

Background: EUS is highly sensitive, specific, and cost-effective for localization of pancreatic neuroendocrine tumors. EUS screening of asymptomatic patients with multiple endocrine neoplasia type 1 has not been described. Methods: EUS was used to evaluate all patients with known or suspected pancreatic neuroendocrine tumors. Asymptomatic patients with either a confirmed genetic or clinical diagnosis of multiple endocrine neoplasia type 1 were evaluated with EUS. The results were correlated with surgical and histopathologic findings. Results: A total of 65 patients with multiple endocrine neoplasia type 1 underwent 132 EUS procedures over an 8-year period, including 13 asymptomatic patients. Five of the 13 asymptomatic patients had normal serum gastrin levels, and 8 had levels less than 4 times the upper limit of normal. EUS demonstrated pancreatic neuroendocrine tumors in 11 of these patients, ranging in size from 0.4 to 4 cm (mean 10 mm). Ten of the 11 patients with tumors at EUS underwent surgical exploration, and 23 of 28 (82%) tumors removed surgically had been identified by EUS. At a mean follow-up of 44 months, no liver or lymph node metastases were demonstrated in any patient. Conclusions: In this first cohort study of asymptomatic patients with multiple endocrine neoplasia type 1 undergoing screening EUS, pancreatic neuroendocrine tumors were identified before the development of significant biochemical test abnormalities. Aggressive early surgical treatment may improve the prognosis for these patients.