Hennebert’s sign due to intralabyrinthine schwannoma – case report

To illustrate how careful examination can reveal signs that may be elicited by an intralabyrinthine schwannoma. A patient referred to a tertiary dizziness referral clinic. The patient underwent extensive vestibular assessment, audiometry, and imaging, including computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI). Signs of central or vestibular pathology were assessed, including the fistula test, as well as audiometric thresholds and imaging abnormalities. 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. 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.