Successful radiosurgery for a growing vestibular schwannoma following partial resection of an ipsilateral transfundal inner ear schwannoma and cochlear implantation: illustrative case.

BACKGROUND: Cochlear implantation has become an effective method of hearing rehabilitation for selected patients with vestibular schwannoma (VS) and nonserviceable hearing who are treated by microsurgical tumor resection, radiotherapy, or observation. However, very little information is available on radiotherapy for VS in the presence of a cochlear implant (CI) in cases in which tumor growth occurs following observation, or when residual tumor growth occurs after microsurgery. OBSERVATIONS: The authors report the case of a 60-year-old woman with successful tumor control of a growing VS by radiosurgery after partial resection of a separate, ipsilateral transfundal inner ear schwannoma (IES) with involvement of the modiolus and CI placement. Hearing with the CI could be preserved for the reported observation time of 3 years postradiosurgery. LESSONS: Even though they are extremely rare, the presence of unilateral multifocal IES and VS must be considered. Although results from a single observation should be interpreted with caution, this case suggests that VS tumor control using radiosurgery appears, in principle, to be possible despite the presence of a CI. Further studies are needed to determine whether radiosurgery could prove to be a potential treatment option for VS despite the presence of a CI in carefully selected cases. https://thejns.org/doi/10.3171/CASE26389.