Intradural microsurgery and extradural gamma knife surgery for hypoglossal schwannoma: case report and review of the literature.

There have been only 26 cases of hypoglossal schwannomas reported to originate intradurally and extend extradurally into the hypoglossal canal. This 31-year-old mother of two children presented with a 5-day history of progressive headache, nausea, vomiting and vertigo. Her neurological exam was significant for nystagmus and left tongue deviation with marked atrophy. An initial head CT revealed extensive left hypoglossal canal erosion with 4th ventricle compression. T1-weighted MR images with contrast revealed a 4x3 cm left cerebellopontine angle non-homogeneously enhancing mass with an intracranial cystic component and prominent extension into the eroded hypoglossal canal. A left lateral suboccipital craniotomy was performed for subtotal microsurgical resection of the intradural posterior fossa mass. A schwannoma was diagnosed after resection and gamma knife surgery (GKS) was performed three months later for the extradural residual tumor without further deficits. This is a rare report of a hypoglossal schwannoma in a young patient who was treated with a multimodality approach in order to minimize risks. A review of the literature and discussion of the respective benefits of microsurgery versus GKS and long-term follow-up issues are presented.