Labyrinthitis ossificans


  • A 2 years old boy
  • History of recent prolong fever for 6 weeks with signs of meningism. Admitted to hospital and treated as viral fever.
  • Parent noticed unresponsive to call for the past one month.
  • ENT examination normal.
  • Hearing test noted profound bilateral hearing loss.
HRCT temporal bone in axial plane
HRCT temporal bone axial plane
HRCT temporal bone coronal plane

CT findings:

  • There is ossification/increased density involving the membranous labyrinths (yellow arrows)
  • Bilateral involvement but more severe on the right side
  • There is soft tissue density within the right middle ear (red arrow) with extension into the mastoid air cells. There is no bone erosion.
  • The ossicles are normal in appearance.

Diagnosis: Bilateral labyrinthitis ossificans and right chronic otitis media

Discussion (labyrinthitis ossificans)

  • Also known as labyrinthine ossification
  • Represent pathological ossification of the membranous labyrinth
  • Usually presented with profound sensorineural hearing loss
  • May have vertigo and/or dizziness
  • Most commonly the end result of otomastoiditis or meningitis
  • Other causes include trauma or surgery, autoimmune ear disease and sickle cell disease
  • Mild disease if hazy increase in density seen within fluid spaces of the membranous labyrinth
  • Moderate disease if focal areas of bony encroachment on fluid spaces of the membranous labyrinth seen
  • Severe disease if membranous labyrinth completely obliterated by bone replacing the fluid spaces
  • This condition may complicate or preclude cochlear implantation
  • In this case soft tissue density of right middle ear is unlikely to be due to cholesteatoma due to no bone erosion and no abnormality of ossicles seen.
Author: radhianahassan