OBJECTIVE: To illustrate how careful examination can reveal signs that may be elicited by an intralabyrinthine schwannoma. PATIENTS: A patient referred to a tertiary dizziness referral clinic. INTERVENTION(S): The patient underwent extensive vestibular assessment, audiometry, and imaging, including computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI). MAIN OUTCOME MEASURE(S): Signs of central or vestibular pathology were assessed, including the fistula test, as well as audiometric thresholds and imaging abnormalities. RESULTS: The patient exhibited unilateral vestibular hypofunction and profound hearing loss in the left ear. Application of a Politzer balloon to the left external auditory canal induced a combination of upbeat nystagmus and horizontal nystagmus to the left, particularly upon pressure release. The CT scan showed no abnormalities. MRI revealed a schwannoma located in the basal and middle turns of the left cochlea extending into the vestibule and in close contact with the stapes. CONCLUSIONS: This case report provides unique evidence of Hennebert’s sign in a patient with an intralabyrinthine schwannoma, highlighting the importance of performing detailed vestibular testing and considering this diagnosis.
Keywords: Cochlea; Fistula test; Hennebert sign; Inner ear schwannoma; Intralabyrinthine schwannoma; Nystagmus; Pressure induced nystagmus; Valsalva; Vestibular schwannoma; Vestibule.