Neuroendocrine Tumor of the Ampulla of Vater: A Rare Neoplasm in an Atypical Site. Report of Three Cases and Review of the Literature

Context The neuroendocrine tumor of the ampulla of Vater represents a rare disease and, although the majority of them are indolent, this neoplasm has a relatively poor prognosis. A quarter of cases of ampullary neuroendocrine tumors have been detected in patients with neurofibromatosis type I (von Recklinghausen's disease). The biological behavior of ampullary neuroendocrine tumor shows no association to the dimension of the tumor and they are more aggressive than non-ampullary duodenal neuroendocrine tumor. The most frequent symptoms are jaundice (60%) and abdominal pain (40%), followed by weight loss (10%). The determination of histopathology is of utmost importance and involves specific immunohistochemical staining. In most ampullary neuroendocrine tumors, the expression of neuroendocrine markers as chromogranin A, neuron specific enolase and synaptophysin, either isolated or in combination is positive. The carcinoid syndrome is uncommon, unless hepatic metastases are present. Most neuroendocrine tumor of the duodenal ampulla is diagnosed incidentally in the duodenoscopy. Case report The authors describe three cases involving neuroendocrine tumor of the ampulla of Vater that were operated upon a single institution and report the etiopathogenic, clinical, diagnostic, therapeutic and prognostic characteristics of this rare neoplasm. Conclusions Neuroendocrine tumors of the ampulla of Vater without invasion and a diameter of <2 cm seem to have a better prognosis. Radical resection should be the standard approach in most patients due to the poor accuracy of preoperative and intraoperative assessments of lymph node involvement and the high incidence of lymph node metastases, even in tumors that are smaller than 2 cm. Received May 04th, 2016 Accepted June 02nd, 2016