Posterior canal dehiscence syndrome caused by an apex cholesteatoma.
OBJECTIVE
To compare audio-vestibular findings caused by a dehiscence of the posterior semicircular canal with those found in the superior canal dehiscence syndrome.


METHODS
Case report.


METHODS
University hospital, tertiary referral center.


METHODS
The 44-year-old woman suffered from a gradual hearing loss with pulse-synchronous tinnitus as well as sound and pressure-induced vertigo.


METHODS
Audio-vestibular testing and high-resolution computed tomography.


METHODS
The superior canal dehiscence syndrome is caused by failure of normal postnatal bone development in the middle cranial fossa leading to absence of bone at the most superior part of the superior semicircular canal. The typical features for this syndrome are sound- and pressure-induced vertigo with torsional eye movements, pulse synchronous tinnitus and apparent conductive hearing loss in spite of normal middle-ear function. We present a patient with very similar symptoms and findings who, instead, had a posterior semicircular canal dehiscence caused by an apex cholesteatoma.


CONCLUSIONS
Patients with semicircular canal dehiscence have common auditory-vestibular features regardless of which of the two vertical semicircular canals is affected. The only obvious difference between the two is the vertical component of the sound and pressure-induced eye movements (which beats in opposite directions).
Brantberg
Krister
K
Department of Audiology, Karolinska Hospital, Stockholm, Sweden. krister.brantberg@karolinska.se
Bagger-Sjöbäck
Dan
D
Mathiesen
Tiit
T
Witt
Hanne
H
Pansell
Tony
T
D000328:Adult; D018424:Cholesteatoma, Middle Ear / Q000150:complications*; D005133:Eye Movements; D005260:Female; D006314:Hearing Loss, Conductive / Q000209:etiology*; D006801:Humans; D012665:Semicircular Canals / Q000473:pathology*; D013577:Syndrome; D014012:Tinnitus / Q000209:etiology*; D014057:Tomography, X-Ray Computed; D014717:Vertigo / Q000209:etiology*