Refractory Radiation Necrosis After Stereotactic Radiosurgery for Cerebellar Arteriovenous Malformation: A Case Report.

Radiation necrosis is a recognized late complication of stereotactic radiosurgery for brain arteriovenous malformations, though it occurs rarely in the cerebellum. While radiation necrosis is typically managed conservatively with corticosteroids, refractory cases may require surgical intervention. A 70-year-old man underwent stereotactic radiosurgery for an incidentally detected left cerebellar arteriovenous malformation. Although complete obliteration was confirmed by digital subtraction angiography 1.5 years after stereotactic radiosurgery, he developed progressive radiation necrosis 2.5 years post-treatment, presenting with dizziness, vomiting, dysarthria, and ataxia. Initial transoral corticosteroid therapy provided symptomatic relief. Seven months later, his symptoms worsened again, and magnetic resonance imaging revealed progressive brainstem edema. Dose escalation of corticosteroids was ineffective, necessitating surgical resection. Histopathology confirmed coagulative necrosis, with remnants of the arteriovenous malformation nidus remaining. Postoperatively, the patient showed significant clinical improvement, with resolution of edema and tapering of steroids. This case highlights the challenges in managing radiation necrosis following stereotactic radiosurgery for cerebellar arteriovenous malformations. While medical therapy remains first-line, surgical resection should be considered in refractory cases to prevent complications associated with prolonged steroid use. Early recognition and intervention are crucial for optimizing patient outcomes.