Histamine-producing neuroendocrine tumor of the ampulla of Vater

Neuroendocrine tumors of the ampulla of Vater are rare (less than 100 cases reported). We report here a new case characterized by histamine secretion, a hitherto unreported feature. Clinical presentation is similar to that of other tumors of the ampulla of Vater In our observation the patient had no ticed urticaria on the right forearm for several months. Tumor of the ampul la was confirmed by endoscopic ultrasonography, while neuroendocrine charac terization was assessed on biopsies after endoscopic sphincterotomy. Histam ine concentration in blood was the only elevated neuroendocrine marker and returned to normal after surgical resection. Histology showed a neuroendocr ine tumor with extension to lymph nodes. On immunohistochemical analysis, p roduction of histamine was confirmed and the diagnosis of mastocytoma was e liminated. In view of the literature, neuroendocrine tumors of the ampulla of Vater al-e associated with a good prognosis (5 year-survival rate: 90%) despite early lymph node involvement.