title: A comparison of patterns of disease extension in keratosis obturans and external auditory canal cholesteatoma.
abstract: OBJECTIVE
  To investigate the different pathways of progression to the middle ear in keratosis obturans (KO) and external auditory canal cholesteatoma (EACC).
  
  
  METHODS
  Retrospective case review.
  
  
  METHODS
  Referral hospital otolaryngology department.
  
  
  METHODS
  Patients with KO or EACC and middle ear disease who underwent surgical management were included. Four ears of 4 patients (mean age, 41.25 yr) were the KO group, and 5 ears of 4 patients (mean age, 49.5 yr) were the EACC group.
  
  
  METHODS
  Intraoperative findings of the middle ear cavity were investigated in KO and EACC groups.
  
  
  RESULTS
  In the KO group, 3 patients had a perforated tympanic membrane and cholesteatoma in the tympanic cavity. The other patient had preoperative right facial palsy. Removal of the keratin plug revealed an adherent tympanic membrane. In intraoperative findings, the tympanic segment of the fallopian canal was found to be eroded because of inflammation. No case initially progressed to the mastoid cavity. Four patients had external auditory canal cholesteatoma with middle ear disease. In EACC group, all patients had initial progression to the mastoid cavity.
  
  
  CONCLUSIONS
  KO tends to progress initially to the tympanic cavity via a diseased tympanic membrane. EACC tends to progress to the mastoid cavity via destruction of the posterior bony canal. This is the first report to investigate differences in pathway of progression to the middle ear cavity in these 2 diseases.
authors.affiliation: Department of Otolaryngology, Jichi Medical University, Saitama Medical Center, Saitama, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shinnabe
authors.forename: Mariko
authors.initials: M
authors.lastname: Hara
authors.forename: Masayo
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Shingo
authors.initials: S
authors.lastname: Matsuzawa
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Naohiro
authors.initials: N
authors.lastname: Yoshida
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Iino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002781:Cholesteatoma / Q000473:pathology / Q000601:surgery*; D018450:Disease Progression; D004424:Ear Canal / Q000473:pathology / Q000601:surgery*; D004427:Ear Diseases / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007642:Keratosis / Q000473:pathology / Q000601:surgery*; D008297:Male; D008416:Mastoid / Q000473:pathology / Q000601:surgery; D008875:Middle Aged