title: Carcinoma with shared pathologic characteristics of both hepatocellular carcinoma and cholangiocarcinoma.
abstract: BACKGROUND
  α-Fetoprotein (AFP) is a useful marker of hepatocellular carcinoma (HCC), and protein induced by vitamin K absence or antagonist II (PIVKA-II) and fucosylated AFP (AFP-L3) are specific tumor markers.
  
  
  OBJECTIVE
  The aim of this article was to report a case of intrahepatic cholangiocarcinoma (CC) with high levels of expression of AFP, AFP-L3, and PIVKA-II.
  
  
  METHODS
  A 70-year-old man weighing 66 kg with a diagnosis of intrahepatic CC presented with a liver tumor 4.0 cm in diameter and elevated concentrations of carbohydrate antigen 19-9 (575 U/mL), PIVKA-II (379 mAU/mL), and AFP (497 ng/mL; AFP-L3, 88.1%). On extended medial hepatic segmentectomy, microscopy showed that the tumor was a CC without HCC. The patient subsequently underwent immunohistochemical assessments using cytokeratin-19, epithelial membrane antigen (EMA), hepatocyte paraffin-1 (HP-1), PIVKA-II, and AFP.
  
  
  RESULTS
  In all specimens, desmoplasia was observed. However, results of immunohistochemistry showed positive results for cytokeratin-19 and EMA; HP-1 results were negative. Results of PIVKA-II and AFP testing in the tumor were positive.
  
  
  CONCLUSIONS
  The case presented here showed characteristics of CC and HCC, whereas the histologic expression of the tumor suggested CC. Based on the literature search, this is the first known report of a case of a CC expressing AFP and PIVKA-II confirmed on immunohistochemical staining. This case is interesting with regard to the ability of the progenitor cells to differentiate HCC and CC.
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hiraoka
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Kurose
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Teru
authors.initials: T
authors.lastname: Kumagi
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Hirooka
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yokota
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Toshiteru
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Utsunomiya
authors.affiliation: Department of Internal Medicine, Matsuyama Johto Hospital, Ehime, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Hirata
authors.affiliation: First Department of Surgery, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ohtani
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Kojiro
authors.initials: K
authors.lastname: Michitaka
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Horiike
authors.affiliation: First Department of Surgery, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
authors.forename: Morikazu
authors.initials: M
authors.lastname: Onji
keywords: combined hepatocellular carcinoma-cholangiocarcinoma; fucosylated α-fetoprotein; hepatocellular carcinoma; vitamin K absence or antagonist 11