Adenocarcinoid tumor of the extrahepatic biliary tract.

The term adenocarcinoid was first coined by Warkel et al in 1978 to describe a group of uncommon low-grade malignant appendiceal tumors with morphologic and histochemical evidence of both glandular (adenocarcinoma) and neuroendocrine (carcinoid) differentiation for which several terms have been used in the past. Although the appendix is the most frequent site of this tumor, similar neoplasms have been reported also in other sites, such as colon, gallbladder, Vater's ampulla, and stomach. The biologic and clinical behavior of adenocarcinoid is still unclear. Provided that it can metastasize, a recent meta-analysis on appendiceal adenocarcinoids showed that right hemicolectomy is not required when the tumor is completely excised and there is no cecal involvement. In this article, the clinicopathologic features of an adenocarcinoid tumor occurring in the extrahepatic biliary tract with infiltration of the common hepatic duct wall that, to the best of our knowledge, represents the first report in this site is described.