Postobliteration Arteriovenous Malformation Mimicking Malignant Change 30 Years After X-Knife Treatment—Case Report and Review of Literature

Background Arteriovenous malformations (AVMs) are potentially dangerous vascular anomalies of the brain that can cause seizures or intracranial hemorrhage in patients if left untreated. Because full excision of these lesions is not always possible in deep or eloquent areas of the brain, radiosurgical advances have gone a long way in the control and treatment of AVMs. Postradiosurgery AVMs are followed closely via outpatient clinics with serial imaging every few months to assess AVM obliteration. Post X-knife treatment AVMs still carry with them some risk of rebleeding and even a chance of malignant transformation. Case Description In this article, we report a case of a post X-knife−treated arteriovenous malformation with the appearance of malignant change on magnetic resonance imaging and thallium-201 on follow-up 30 years after treatment. Imaging with magnetic resonance angiography showed obliteration of the lesion but progressive change in size with new soft tissue components, which suggests radiation-related secondary malignancy. Conclusions Surgery was arranged, and pathology results indicate no malignant change.