title: [Cyst formation after gamma knife radiosurgery for trigeminal schwannoma: a case report].
abstract: Radiosurgery for small vestibular schwannomas is an established and effective treatment, and it has been used for trigeminal schwannoma recently. Delayed cyst formation is well recognized as a complication after gamma knife radiosurgery for arteriovenous malformation. We encountered a case of delayed cyst formation after gamma knife radiosurgery for trigeminal schwannoma. An 81-year-old male presented with abducens palsy and ataxia 6 years after gamma knife radiosurgery for trigeminal schwannoma. A cyst development in the posterior fossa was identified, and the brain stem was compressed by the cyst. The cyst was removed and the abducens palsy and ataxia improved within a month. Histological findings revealed variable tumor tissue in the cyst wall. Delayed cyst formation should be recognized as a complication after radiosurgery for schwannoma.
authors.affiliation: Department of Neurosurgery, Saitama Saiseikai Kurihashi Hospital, 714-6 Kouemon, Kurihashi-machi, Kitakatsushika-gun, Saitama 349-1105, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wanifuchi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Watanabe
mesh_terms: D000369:Aged, 80 and over; D003390:Cranial Nerve Neoplasms / Q000601:surgery*; D003560:Cysts / Q000209:etiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009442:Neurilemmoma / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects*; D020433:Trigeminal Nerve Diseases / Q000601:surgery*