Case Report
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jun 14, 2013; 19(22): 3524-3527
Published online Jun 14, 2013. doi: 10.3748/wjg.v19.i22.3524
Hepatoid adenocarcinoma of the extrahepatic duct
Yu Wang, Ying-Ying Liu, Gui-Ping Han
Yu Wang, Ying-Ying Liu, Gui-Ping Han, Department of Pathology, the 2nd Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China
Author contributions: All authors contributed equally to this work; Han GP performed the pathological diagnosis; Wang Y and Liu YY summarized the clinical materials and generated the photographs; all authors wrote the manuscript.
Supported by The Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China, No. 2009-1001
Correspondence to: Gui-Ping Han, PhD, Professor of Medicine, Department of Pathology, the 2nd Affiliated Hospital of Harbin Medical University, Xuefu Road 246, Nanggang District, Harbin 150086, Heilongjiang Province, China.
Telephone: +86-451-86296970 Fax: +86-451-86296970
Received: January 10, 2013
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.

Keywords: Extrahepatic bile ducts, Hepatocellular, Adenocarcinoma, Immunohistochemistry, Surgical pathology, Differential diagnosis

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.