Radiosurgery is relatively safe procedure, but there is still a risk of radiation necrosis as well as incomplete obliteration of the nidus of the arteriovenous malformation. But, sometimes cancer induction is the most important somatic effect of GK radiosurgery. Persons exposed therapeutically received comparatively high doses, and their susceptibility to the effects of radiation might have been influenced by the medical condition for which treatment was being given.

     We have experienced radiosurgery associated tumor after GammaKnife radiosurgery and our goal was to describe this.

     57-year-male treated with GK radiosurgery for both occipital dural AVF after two sessions of embolization. 4 years later, Lt hemiparesis was noted. Brain MRI showed a right occipital tumor. At resection, the biopsy showed glioblastoma. He received radiotherapy and Temodar chemotherapy.

     We report the clinical and imaging findings in this case.

     In our case, a tumor developed 4 years after radiosurgery in cerebral dural AVF.  Usually, the latency period was 6-21 years. Radiation associated brain tumor was all malignant tumor, and our case was a glioblastoma.

     This is a single case retrospective report.

     GK radiosurgery is safe and effective strategy for benign tumor, vascular lesion, etc, but radiation-associated astrocytoma can develop after GK radiosurgery very rarely.  

     We should be suspicious for the onset of a tumor if the patient''s condition is worse after Gamma-Knife radiosurgery in dural AVF.