title: Nasopharyngeal carcinoma in situ in nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To assess the presence of carcinoma in situ (CIS) in patients with nasopharyngeal carcinoma (NPC) and to see if the number of biopsy sites facilitates detection of CIS.
  
  
  METHODS
  Formalin fixed, paraffin wax embedded biopsy specimens (n = 285) from 187 patients with NPC in 1987 were studied for the presence of CIS as well as for the histological assessment of the subtype of CIS.
  
  
  RESULTS
  Fifteen (8.0%) patients had CIS, representing 8.3% of all new patients with NPC and 11.6% of patients with persistent disease or relapse. CIS was undifferentiated or poorly differentiated, no cases of well differentiated squamous cell CIS were identified. There was no significant difference in the incidence of CIS when multiple endoscopic biopsy specimens were taken rather than single forceps biopsy specimens.
  
  
  CONCLUSIONS
  CIS can only be identified in a few patients with NPC largely because of late presentation with advanced disease at the time of diagnosis and the focal nature of the dysplastic process. The presence of dysplasia in relapses of NPC suggests that these tumours may be second growths rather than regrowths of a primary tumour.
authors.affiliation: Department of Pathology, University of Hong Kong.
authors.forename: C W
authors.initials: CW
authors.lastname: Chan
authors.forename: J M
authors.initials: JM
authors.lastname: Nicholls
authors.forename: J S
authors.initials: JS
authors.lastname: Sham
authors.forename: P
authors.initials: P
authors.lastname: Dickens
authors.forename: D
authors.initials: D
authors.lastname: Choy
mesh_terms: D002278:Carcinoma in Situ / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D002295:Carcinoma, Transitional Cell / Q000473:pathology; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D016609:Neoplasms, Second Primary / Q000473:pathology