Approach to the Diagnosis of Hepatoid Adenocarcinoma, an Under-reported Entity: Case Series and Review of Literature

Hepatoid adenocarcinoma is a rare type of extra-hepatic adenocarcinoma which exhibits morphological, functional, and immunohistochemical features of hepatocellular carcinoma, hence correct diagnosis poses a challenge. The most frequent site of this tumor is stomach and rarely occurs in ovaries, lung, gallbladder, pancreas, uterus, and other sites. We present four cases of hepatoid adenocarcinoma of our hospital at rare sites like lungs and gallbladder along with literature review and a simplified approach to diagnosis. In absence of adequate immunohistochemistry or radiological findings often this entity is missed or misdiagnosed as metastatic hepatocellular carcinoma. We have analyzed these hepatoid adenocarcinoma cases in terms of various clinical, serological, histo-morphological, and immunohistochemical parameters, and propose a systematic approach to correctly diagnose this entity.