title: Undifferentiated carcinoma of the liver: a case report with immunohistochemical analysis.
abstract: BACKGROUND
  Undifferentiated carcinoma (UC) of the liver is extremely rare, and its clinicopathological characteristics have not been fully elucidated.
  
  
  METHODS
  The present study reports the case of a 56-year-old male with UC of the liver. At 16 days post-admission, the patient suddenly succumbed due to intra-abdominal bleeding resulting from a ruptured liver. Macroscopic examination revealed that the hepatic parenchyma was almost completely replaced by innumerable minute nodules. Microscopically, the tumor demonstrated a diffuse proliferation of anaplastic cells that were positive for epithelial membrane antigen and neuron-specific enolase, suggesting neuroendocrine differentiation. Grimelius and Fontana-Masson staining were negative. Neuroendocrine markers were also negative, including chromogranin A, synaptophysin, and S-100 protein. Cytokeratin markers and mesenchymal markers were all negative. Tumor markers, such as α-fetoprotein and carcinoembryonic antigen, were also negative.
  
  
  CONCLUSIONS
  Although larger studies involving more patients are required to establish a therapeutic strategy, appropriate chemotherapy following an early diagnosis may be important to UC of the liver because the tumor behaves in an aggressive way.
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan. tksmaeda9@gmail.com.
authors.forename: Takashi
authors.identifier: http://orcid.org/0000-0002-9308-2329
authors.initials: T
authors.lastname: Maeda
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kayashima
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Imai
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Takeishi
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Harada
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Tsujita
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Matsuyama
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tsutsui
authors.affiliation: Department of Surgery, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital, 1-9-6 Senda-machi, Naka-ku, Hiroshima, 730-8619, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsuda
keywords: Liver cancer; Neuroendocrine carcinoma; Undifferentiated carcinoma