Isolated intralabyrinthine schwannoma.

Although most vestibular schwannomas arise in the internal auditory canal, a more peripheral site of origin is possible. We report a case of isolated schwannoma limited to the labyrinthine vestibule. Our description of the location of this tumor is further documentation that schwannomas can arise from the terminal vestibular nerve fibers to the cristae or maculae. Either the nerve roots of the superior vestibular nerve to the utricle and horizontal and superior semicircular canal cristae, or the nerve roots of the inferior vestibular nerve to the saccule and posterior semicircular canal crista may have been the locus of origin of this unusual tumor. Intralabyrinthine schwannoma should be included in the differential diagnosis in the face of progressive auditory and vestibular dysfunction. Because conventional roentgenographic studies usually fail to demonstrate the presence of schwannoma in this location surgical exploration of the labyrinthine vestibule in the presence of unserviceable hearing and incapacitating vertigo is indicated.