title: Fine needle aspiration diagnosis of combined hepatocellular carcinoma and cholangiocarcinoma. A case report.
abstract: BACKGROUND
  The finding of a dual cellular population in a liver fine needle aspirate, in the appropriate clinical context, raises many differential diagnoses, including combined hepatocellular carcinoma and cholangiocarcinoma, a relatively rare form of primary liver carcinoma.
  
  
  METHODS
  A hepatitis C-positive patient with cirrhosis and rapidly worsening liver failure underwent fine needle aspiration of two radiologically detected liver masses. Abundant material composed of two cell populations, one typical of hepato-cellular carcinoma and one with features of mucin-producing adenocarcinoma, were found. Both components were positive for low molecular weight cytokeratins, the hepatocellular carcinoma component was positive for carcinoembryonic antigen (CEA) (B18 isoform) in a typical canalicular pattern, and the cholangiocarcinomatous component was positive for high molecular weight cytokeratins and CEA (isoforms B18 and D14). Both components were negative for alpha-fetoprotein.
  
  
  CONCLUSIONS
  Identification of a dual cell population, such as this, in a liver fine needle aspirate should raise the possibility of a combined hepatocellular carcinoma and cholangiocarcinoma and is unlikely to represent metastatic disease. This variant of hepatocellular carcinoma is rare and constitutes 1-5% of primary liver carcinomas. It is important to make this diagnosis and to separate this tumor from the usual hepato-cellular carcinoma and metastatic carcinoma, since it may give rise to pure cholangiocarcinomatous metastatic deposits, adding to the diagnostic difficulties.
authors.affiliation: Mallory Institute of Pathology, Boston University School of Medicine, Massachusetts 02118, USA.
authors.forename: D
authors.initials: D
authors.lastname: Gibbons
authors.forename: A
authors.initials: A
authors.lastname: de las Morenas
mesh_terms: D000368:Aged; D001707:Biopsy, Needle; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000473:pathology*; D018279:Carcinoma, Signet Ring Cell / Q000175:diagnosis / Q000473:pathology; D018281:Cholangiocarcinoma / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000473:pathology