Published online Jun 14, 2013. doi: 10.3748/wjg.v19.i22.3524
Revised: April 29, 2013
Accepted: May 22, 2013
Published online: June 14, 2013
Hepatoid carcinoma is a unique type of extrahepatic tumor associated with hepatic differentiation and displays the morphological and functional features of hepatocellular carcinoma. Hepatoid carcinoma of the extrahepatic duct has rarely been reported in the literature. We report a 62-year-old man who presented with epigastric discomfort, xanthochromia, dull pain of the right shoulder, nausea and pruitus. Microscopic examination of the extrahepatic duct indicated that the tumor was primarily composed of “hepatoid cells”, which were characterized by an eosinophilic cytoplasm, enlarged nucleus and prominent nucleoli. The cells were arranged in nests or proliferated in a trabecular pattern. Immunohistochemistry indicated that the tumor cells were positive for hepatocyte paraffin 1 and cytokeratins 8 and 18. Based on these findings, this case was diagnosed as hepatoid carcinoma of the extrahepatic duct.
Core tip: Hepatoid adenocarcinoma (HAC) is a rare type of extrahepatic adenocarcinoma that resembles hepatocellular carcinoma. Although the stomach is the most common location for this tumor, the lung, pancreas, esophagus, papilla of Vater, colon, urinary bladder, renal pelvis, ovaries, uterus and cervix have also been reported as primary locations. To the best of our knowledge, HAC arising primarily from the extrahepatic duct has not previously been reported in the literature. This report presents a rare case of HAC of the hepatic duct and performs a differential diagnosis based on immunochemical results, detailed clinical history and endoscopic findings.