Thursday, September 30, 2010

Cholesteatoma- HRCT

Non contrasted temporal bone CT reveals a soft tissue mass in the right middle ear and Prussak’s space with associated erosions of the scutum, epitympanum walls, lateral semicircular canal, tegmen tympani and middle ear ossicles. It is also extending in to the mastoid air cells.
Discussion:
  • An acquired cholesteatoma is a collection of exfoliated squamous epithelium and debris.
  • Cholesteatomas often begin at the pars flaccida of the tympanic membrane and grow in Prussak's space of the temporal bone and produce inflammatory reaction.
  • Cholesteatomas typically occur in the setting of chronic dysfunction of the Eustachian tubes and recurrent otitis media.
  • Cholesteatomas can be as small as a couple of millimeters in size or can grow to fill the entire middle ear.
  • Erosions of the scutum and ossicles are commonly seen.
  • The presence of bony erosions or expansion are strong support of cholesteatoma over chronic otomastoiditis.
  • Acquired cholesteatomas occur in children and adults.
  • Most common presenting symptoms include ear discharge, hearing loss, ear pain and vertigo.
  • Without treatment cholesteatomas will progressively increase in size.
  • Complications include: Hearing loss, CN 7 palsy, venous sinus thrombosis, semicircular canal fistulas, and intracranial invasion.
  • Early surgical intervention usually results in complete eradication and preservation of hearing.
Differential diagnosis:
  1. Acquired cholesteatoma
  2. Chronic otomastoiditis
  3. Middle ear cholesterol granuloma
  4. Glomus tympanicum paraganglioma

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