title: A case of inflammatory hepatocellular adenoma displaying an unusual histological pattern.
abstract: Hepatocellular adenoma (HCA) is a rare type of liver tumor. Here, we report a variant case of HCA in a 56-year-old Japanese man which displayed unusual histological features. The patient had undergone surgery for esophageal and gastric cancer 2 years prior. A computed tomography scan performed in the follow-up period detected a single lesion (diameter 1.4 cm) in the right posterior lobe of the liver, leading to a partial hepatectomy. Histologically, the lesion was composed of two different types of cells. The larger cells, which accounted for most of the cells in the tumor, exhibited granular and eosinophilic cytoplasm, large nuclei and apparent nucleoli. These cells, which were designated the common cells, were typical of the HCA. The other cells, which were designated the pyknotic cells, were smaller, possessed an eosinophilic, homogeneous cytoplasm and pyknotic small nuclei, but did not contain nucleoli. Immunohistochemically, the common cells reacted strongly positive for C-reactive protein and serum amyloid A, which is compatible with a diagnosis of inflammatory HCA; in contrast, the pyknotic cells tested negative for these molecules. Since the pyknotic cells tested positive for several markers of apoptosis, they were considered to be apoptotic. In addition, as the common cells demonstrated a higher ki-67 labeling index, the lesion was considered to display upregulated cell kinetics, i.e. increases in both cell growth and death. Although HCA is a rare type of tumor, there have been several reports on HCA variants. The case reported here is that of a new type of HCA variant that demonstrated an unusual histological pattern and upregulated cell kinetics.
authors.affiliation: Department of Pathology, The Cancer Institute of the Japanese Foundation for Cancer Research (JFCR) and Clinicopathology Center, The Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan. hkanda-ind@umin.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanda
authors.affiliation: Department of Pathology, The Cancer Institute of the Japanese Foundation for Cancer Research (JFCR) and Clinicopathology Center, The Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.|Department of Medical Laboratory Sciences, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Furuta
authors.affiliation: Department of Pathology, The Cancer Institute of the Japanese Foundation for Cancer Research (JFCR) and Clinicopathology Center, The Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.|Department of Pathology and Clinical Laboratories, National Cancer Center Hospital, 5-1- 1 Tsukiji, chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Motoi
authors.affiliation: Department of Pathology, The Cancer Institute of the Japanese Foundation for Cancer Research (JFCR) and Clinicopathology Center, The Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Kakita
authors.affiliation: Department of Pathology, The Cancer Institute of the Japanese Foundation for Cancer Research (JFCR) and Clinicopathology Center, The Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Sugiura
authors.affiliation: Department of Radiology, The Cancer Institute Hospital of JFCR, Tokyo, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Unno
authors.affiliation: Department of Radiology, The Cancer Institute Hospital of JFCR, Tokyo, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsueda
authors.affiliation: Department of Surgery, The Cancer Institute Hospital of JFCR, Tokyo, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Saiura
authors.affiliation: Department of Pathology, School of Medicine, Nihon University, 30-1 Ohyaguchi-Kamichou, Itabashi-ku, Tokyo, 173-8610, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sugitani
authors.affiliation: Department of Pathology, The Cancer Institute of the Japanese Foundation for Cancer Research (JFCR) and Clinicopathology Center, The Cancer Institute Hospital of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishikawa
mesh_terms: D018248:Adenoma, Liver Cell / Q000473:pathology* / Q000601:surgery; D002097:C-Reactive Protein / Q000032:analysis; D006498:Hepatectomy; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology; D019394:Ki-67 Antigen / Q000032:analysis; D008113:Liver Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D000685:Serum Amyloid A Protein / Q000032:analysis
chemical_list: D019394:Ki-67 Antigen; D000685:Serum Amyloid A Protein; D002097:C-Reactive Protein
keywords: Apoptosis; Hepatocellular adenoma; Histology