title: Clinical behavior and pathogenesis of secondary acquired cholesteatoma with a tympanic membrane perforation.
abstract: CONCLUSIONS
  The pathogenesis of secondary acquired cholesteatoma with a tympanic membrane (TM) perforation is very different from that of other types of cholesteatoma. This disease should be clearly categorized as a different type of cholesteatoma.
  
  
  OBJECTIVE
  Primary cholesteatoma generally arises from retraction of the squamous epithelium of the TM. However, in rare cases, epithelial invasion occurs from the edge of the TM perforation and migrates to the medial surface of the TM and middle ear cavity. The aim of this study was to evaluate the clinical features of secondary acquired cholesteatoma with a TM perforation.
  
  
  METHODS
  We investigated 13 ears that underwent surgical treatment after the diagnosis of secondary acquired cholesteatoma with a TM perforation. Patient backgrounds, the preoperative appearances of TM, intraoperative findings, and histopathological findings were investigated.
  
  
  RESULTS
  The average age was much higher than that of patients with other types of cholesteatoma, suggesting that it must require long periods of time to establish the disease. The common area of the epithelial invasion was on the superior part of the TM perforation around the tip of the malleus handle. The tendon of the tensor tympani muscle plays an important role as an extension route for this disease.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Niigata University Faculty of Medicine , Niigata , Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Kuniyuki
authors.initials: K
authors.lastname: Takahashi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Morita
authors.forename: Sugata
authors.initials: S
authors.lastname: Takahashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018424:Cholesteatoma, Middle Ear / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D004724:Endoscopy / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D018058:Tympanic Membrane Perforation / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D014433:Tympanoplasty / Q000379:methods*