Unilateral Labyrinthine Ossificans
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This was a patient who had a long-standing history of
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chronic otitis media for which a mastoidectomy was performed.
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When we look at the right side,
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we see that the patient has a canal wall up mastoidectomy
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with a defect in the mastoid air cells.
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However,
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there is still opacification of some
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of these mastoid air cells.
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The middle ear ossicles are identified, and we see
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the incudostapedial joint with the stapes here.
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As we continue scrolling,
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we notice that there is bony obliteration of the lateral
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semicircular canal, and we kind of lose the
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limbs of the superior semicircular canal.
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So if we look at the contralateral side,
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we are identifying the two limbs of the superior
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semicircular canal with the semi arcuate vessel
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coursing between it. On the right side,
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we don't see those limbs of the semicircular canal.
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And in fact,
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the posterior semicircular canal is also missing in this
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individual, as is the lateral semicircular canal,
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where we see bony obliteration or bony ingrowth.
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Note that the cochlea looks pretty good,
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except its basal turn.
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So we have the apical turn, the middle turn,
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and at the basal turn, you have ingrowth of
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bone into the basal turn of the cochlea,
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comparing the right side from the left side.
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So once again,
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this is an example of unilateral labyrinthitis ossificans
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as a complication of chronic otitis media.
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And at some point,
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this chronic otitis media must have created a labyrinthine
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fistula and inflammation that got into the labyrinthine
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structures to account for the labyrinthitis ossificans.
David M Yousem, MD, MBA
Professor of Radiology, Vice Chairman and Associate Dean
Johns Hopkins University
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