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.

     

     57-year-male treated with GK raiosurgery for both occipital dural AVF after two times embolization. 4 years later, Lt hemiparesis was developed, Brain MRI showed right occipital tumor. Tumor operation biospy result was glioblastoma. He received radiotherapy and Temodar chemotherapy.

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

     This was a single patient experience.

     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 of a new  tumor if the patient''s condition is worse after Gamma-Knife radiosurgery for dural AVF or other disorders.