title: Cholesteatoma behind an intact tympanic membrane: histopathologic evidence for a tympanic membrane origin.
abstract: BACKGROUND
  Several theories have been proposed with respect to the origin and pathogenesis of cholesteatoma behind an intact tympanic membrane.
  
  
  METHODS
  The authors describe a case of cholesteatoma behind an intact tympanic membrane in a 71-year-old man with a history of tympanic membrane retraction fixed to the incus without evidence of a perforation. The membrane eventually became detached, and remnants of keratinizing squamous epithelium were found on the incus.
  
  
  CONCLUSIONS
  Mechanisms such as metaplasia, ectopic epidermis rests, or ingrowth of meatal epidermis have been proposed to explain the pathogenesis of cholesteatoma behind an intact tympanic membrane. These findings, based on temporal bone histopathology, support the role of an acquired epidermal rest.
  
  
  CONCLUSIONS
  This case report provides evidence that cholesteatoma behind an intact tympanic membrane can be established from a resolved retraction of the pars tensa of the tympanic membrane.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth Hospital, University of Bochum, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Sudhoff
authors.forename: F H
authors.initials: FH
authors.lastname: Linthicum
mesh_terms: D000368:Aged; D018424:Cholesteatoma, Middle Ear / Q000150:complications / Q000175:diagnosis*; D018450:Disease Progression; D004817:Epidermis / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D008297:Male; D014432:Tympanic Membrane / Q000473:pathology*