[Epidermoid cysts of the fourth ventricle mimicking benign paroxysmal positional vertigo].
OBJECTIVE
To report a case of atypical positional vertigo revealing a fourth ventricle epidermoid cyst.


METHODS
We report a case of a thirty-year-old woman suffering from positional vertigo with downbeat nystagmus. Except for these symptoms, the physical examination was normal, apart from intermittent headaches. On videonystagmography, a decrease in the average speed of beats and lowered benefits obtained by slow motion were noted. MRI revealed a fourth ventricle epidermoid cyst.


RESULTS
Physical examination may provide several signs that are likely to enable the examiner to distinguish between central nervous system or peripheral vertigos. Atypical symptoms such as a downbeat nystagmus, a lack of reversal in nystagmus beats when returning to the sitting position and a lack of a latency period in vertigo and nystagmus occurrence during the Dix-Hallpike maneuver suggest a central nervous system etiology.


CONCLUSIONS
With atypical symptoms noted when questioning the patient or during physical examination, a central nervous system etiology should be mentioned and explored with cerebral MRI.
Trijolet
J-P
JP
Service ORL & CCF, CHU Bretonneau, 2, boulevard Tonnellé, 37000 Tours, France.
Pondaven-Letourmy
S
S
Robier
A
A
Morinière
S
S
D000328:Adult; D003937:Diagnosis, Differential; D004814:Epidermal Cyst / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D020546:Fourth Ventricle / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D012720:Severity of Illness Index; D014717:Vertigo / Q000175:diagnosis*