title: Histological subtypes and characteristic structures of HPV-associated oropharyngeal carcinoma: study with Japanese cases.
abstract: BACKGROUND
  Human papillomavirus-associated oropharyngeal carcinoma (HPV-OPC) is clinicopathologically distinct entity from the HPV-unassociated one (nHPV-OPC). This study aimed to determine the relationship between histological subtypes of OPC and HPV status for Japanese cases and to identify histological structures of HPV-OPC.
  
  
  METHODS
  66 OPC cases were categorized into conventional squamous cell carcinoma (SCC) and the variants. Conventional SCC was subcategorized into keratinizing (KSCC), non-keratinizing (NKSCC), and hybrid SCC (HSCC). HPV status of all cases was determined using p16-immunohistochemistry and HPV-DNA ISH.
  
  
  RESULTS
  Two histological subtypes, NKSCC and HSCC, tended to be HPV-OPC and KSCC tended to be nHPV-OPC with statistical significance. Two histological structures, abrupt keratinization, defined in the text, and comedo-necrosis among non-maturing tumor island, were observed for 58.1% and 38.7% of HPV-OPC, and tended to exist for HPV-OPC with statistical significance.
  
  
  CONCLUSIONS
  This study showed the association of NKSCC/HSCC with HPV-OPC in Japanese cases, and two histological structures, abrupt keratinization and comedo-necrosis among non-maturing island, were considered characteristic histological features of HPV-OPC.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1816432541113073.
authors.forename: Mitsuhisa
authors.initials: M
authors.lastname: Fujimaki
authors.affiliation: Department of Human Pathology, Juntendo University School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. yfuku@juntendo.ac.jp.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Fukumura
authors.forename: Keiko
authors.initials: K
authors.lastname: Mitani
authors.forename: Aiko
authors.initials: A
authors.lastname: Kurisaki
authors.forename: Junkichi
authors.initials: J
authors.lastname: Yokoyama
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Ikeda
authors.forename: Takashi
authors.initials: T
authors.lastname: Yao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D014408:Biomarkers, Tumor / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000145:classification* / Q000473:pathology / Q000821:virology*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D007564:Japan; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000145:classification* / Q000473:pathology / Q000821:virology*; D009960:Oropharynx / Q000378:metabolism / Q000473:pathology; D027383:Papillomaviridae / Q000235:genetics; D030361:Papillomavirus Infections / Q000150:complications*; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004279:DNA, Viral