title: Nasopharyngeal carcinoma: posttreatment changes of imaging findings.
abstract: OBJECTIVE
  The purpose of this study was to determine the radiologic results of nasopharyngeal carcinoma (NPC) that showed complete responses on follow-up imaging studies after radiation therapy.
  
  
  METHODS
  This study is a retrospective review of 23 patients (18 male, 5 female, aged 15-71 years; mean age, 48.5 years) affected with NPC, from August 1995 to July 2000, who were examined with magnetic resonance imaging or computed tomography scan before and after either radical radiotherapy or chemoradiotherapy. The median follow-up was 24.7 months and ranged from 12 to 48 months. We analyzed the primary tumors by ascertaining/measuring tumor size, depth, middle ear effusion, skull base invasion, and lymphadenopathy. The treatment responses for primary tumors were classified as either atrophy, scar (asymmetric elevation without enhancement), or normalized. The tumor response and the appearance of bone regeneration in the previous destructive part of the skull base were also recorded.
  
  
  RESULTS
  The 23 patients consisted of 12 superficial tumors, for whom treatment results were normalized in 10, atrophy in 1, and scar in 1 and 11 deep tumors for whom treatment results were scar in 6, normalized in 3, and atrophy in 2. Skull base invasion was detected in 6 patients, 5 of whom showed complete healing of skull base destruction after radiotherapy. However, the other patient exhibited an unusual hyperostotic change in the skull base mimicking fibrous dysplasia of the skull base.
  
  
  CONCLUSIONS
  The superficial tumors tended to be radiologically normalized even when they were large. However, the deep tumors mainly changed to scar after radiation therapy. On the other hand, skull base invasion could be normalized after radiotherapy.
authors.affiliation: Department of Radiology, Institute of Radiation Medicine, Seoul National University College of Medicine, Korea.
authors.forename: Young Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Moon Hee
authors.initials: MH
authors.lastname: Han
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Cha
authors.forename: Myung Whun
authors.initials: MW
authors.lastname: Sung
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Kim
authors.forename: Kee-Hyun
authors.initials: KH
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D012189:Retrospective Studies; D019291:Skull Base / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed