title: External auditory canal cholesteatoma: clinical and imaging spectrum.
abstract: OBJECTIVE
  Cholesteatoma is an inflammatory lesion of the temporal bone that uncommonly involves the external auditory canal (EAC). In this large case series, we aimed to define its imaging features and to determine the characteristics most important to its clinical management.
  
  
  METHODS
  Thirteen cases of EAC cholesteatoma (EACC) were retrospectively reviewed. Clinical data were reviewed for the history, presentation, and physical examination findings. High-resolution temporal bone CT scans were examined for a soft-tissue mass in the EAC, erosion of adjacent bone, and bone fragments in the mass. The middle ear cavity, mastoid, facial nerve canal, and tegmen tympani were evaluated for involvement.
  
  
  RESULTS
  Patients presented with otorrhea, otalgia, or hearing loss. Eight cases were spontaneous, and five were postsurgical or post-traumatic. CT imaging in all 13 cases showed a soft-tissue mass with adjacent bone erosion. Intramural bone fragments were identified in seven cases. This mass most often arose inferiorly (n = 8) or posteriorly (n = 8), but it was circumferential in two cases. We noted middle ear extension (n = 5), mastoid involvement (n = 4), facial canal erosion (n = 2), and tegmen tympani dehiscence (n = 1).
  
  
  CONCLUSIONS
  Temporal bone CT shows EACC as a soft-tissue mass within the EAC, with adjacent bone erosion. Bone fragments may be present within the mass. The cholesteatoma may extend into the mastoid or middle ear, or it may involve the facial nerve canal or tegmen tympani. Recognition of this entity and its possible extension is important because it may influence clinical management.
authors.affiliation: Department of Radiology, Division of Neuroradiology, University of Utah School of Medicine, Salt Lake City, USA.
authors.forename: Marta E
authors.initials: ME
authors.lastname: Heilbrun
authors.forename: Karen L
authors.initials: KL
authors.lastname: Salzman
authors.forename: Christine M
authors.initials: CM
authors.lastname: Glastonbury
authors.forename: H Ric
authors.initials: HR
authors.lastname: Harnsberger
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Kennedy
authors.forename: Clough
authors.initials: C
authors.lastname: Shelton
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018424:Cholesteatoma, Middle Ear / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004424:Ear Canal / Q000000981:diagnostic imaging*; D004432:Ear, Middle / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008416:Mastoid / Q000000981:diagnostic imaging; D008875:Middle Aged; D010014:Osteolysis / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D013701:Temporal Bone / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed