Clinicians evaluating patients with Hennebert's sign should include intralabyrinthine schwannoma in the differential diagnosis, even though it is a rare cause.

Expanding the known differential diagnoses for Hennebert's sign helps prevent misdiagnosis and delays in treating inner-ear tumors.

1. 01Hennebert's sign (pressure-induced nystagmus) is typically linked to syphilis or perilymph fistula, not inner-ear tumors.
2. 02This case report links Hennebert's sign to intralabyrinthine schwannoma for the first time (or rarely).