Intratumoral bleeding in meningioma after gamma knife radiosurgery.

Object. The authors evaluated whether gamma knife radiosurgery (GKS) could be a causative factor in intratumoral bleeding in meningiomas. Methods. Gamma knife radiosurgery was used in the treatment of 173 meningiomas during a 10-year period. Four patients suffered post-GKS intratumoral hemorrhage. The course in these patients was reviewed. Four of 173 patients suffered an intratumoral hemorrhage during a follow-up period of 1 to 8 years. The risk of intratumoral bleeding after GKS for meningioma was 2.3%. Intracystic hemorrhage occurred in two patients 1 and 5 years, respectively, after radiosurgery. In the other two cases intratumoral bleeding occurred 2 and 8 years, respectively, after radiosurgery. Histological examination in three cases found no specific findings related to the postradiosurgical changes. Conclusions. Because the reported risk of spontaneous intratumoral bleeding in meningiomas is 1.3 to 2.7%, the incidence in this series was not unduly high. Radiosurgery itself could not be shown to b...