Hepatoid adenocarcinoma (HAC) is a rare extrahepatic tumor distinguished by having both hepatoid and adenomatous features, which can make the diagnosis challenging. Although it mostly originates in the stomach, several other sites of origin have been reported. We report a case of HAC originating in the duodenum, a very unusual location. We also discuss an approach to the diagnosis of HAC using morphological and immunohistochemical features, and explore possible therapeutic options.