Cholesteatoma

Cholesteatoma is a special form of chronic otitis media in which keratinizing squamous epithelium grows from the tympanic membrane or the auditory canal into the middle ear mucosa or mastoid. The presence of abnormal epithelium in an abnormal location triggers an inflammatory response that can destroy surrounding structures such as the ossicles. Cholesteatomas may be congenital or acquired later in life. Acquired cholesteatomas are usually associated with chronic middle ear infection. Cardinal symptoms are painless otorrhea and progressive hearing loss. Important diagnostic procedures include mastoid process x-rays, temporal bone CT scans, and audiometric tests. Left untreated, erosion of the surrounding bone by a cholesteatoma can lead to facial nerve palsy, extradural abscess, and/or sigmoid sinus thrombosis. Therefore, even if a cholesteatoma is asymptomatic, surgery is always indicated. Surgical treatment involves tympanomastoidectomy to excise the cholesteatoma, followed by repair of the damaged middle ear structures.

Keratinizing squamous epithelium grows from the tympanic membrane or the auditory canal into the middle ear mucosa or mastoid air cells.

• Congenital cholesteatoma
  • Present at birth
  • Embryonic nests of epidermal cells that remain in the middle ear
• Acquired cholesteatoma (more common)
  • Primary: eustachian tube dysfunction → tympanic membrane epithelium retracts inwards → retraction pocket
  • Secondary: Epithelium migrates inwards through a perforation in the tympanic membrane, which is commonly caused by recurrent/chronic otitis media.

References:^[1]

• May be asymptomatic
• Painless otorrhea; (scant but foul-smelling discharge from the affected ear)
• Conductive hearing loss
  • Occurs late in primary cholesteatoma
  • Occurs early in secondary cholesteatoma

References:^[1][2][3]

• Otoscopic findings:
  • Primary acquired: retraction pocket with squamous epithelium and debris; that often appears as a brown, irregular mass
  • Congenital and secondary acquired: white or pearly mass behind the tympanic membrane
• Imaging: to assess the degree of bone destruction
  • X-ray of the mastoid process
  • CT scan of the temporal bone
  • MRI is only indicated if intracranial extension is suspected.
• Audiometry: to assess the degree of hearing loss

References:^[1][2][3]

• Surgery is always indicated because of the risk of complications. ^[2]
  • Excision of the cholesteatoma (by canal wall-up or canal wall-down mastoidectomy) to control the discharge and create a dry ear
  • Reconstruction of the middle ear structures and sound-conducting apparatus

• Destruction of ear ossicles ^[1]
• Perilymph fistula
• Facial nerve paralysis
• Erosion of temporal bone → extradural abscess, meningitis, sigmoid sinus thrombosis
• Aural polyp

We list the most important complications. The selection is not exhaustive.