Ampulla of Vater, Adenocarcinoma, Large cell neuroendocrine carcinoma, Collision tumor"/>
Most tumors affecting Vater's ampulla are adenocarcinomas, but a neuroendocrine carcinoma in the ampulla of Vater is extremely rare. The coexistence of these two tumors has been reported in only a few cases. Here, we report a rare case of a collision tumor of the ampulla of Vater with an adenocarcinoma and a large cell neuroendocrine carcinoma. (Korean J Gastrointest Endosc 2011;42:127-130)