ABSTRACT
A 36-year-old man was diagnosed with a right temporal lobe grade II cerebral arteriovenous malformation (cAVM) and was treated with radiosurgery. At nine months after the cAVM radiosurgery, the patient began to develop bilateral focal narrowing at the M1 segments of the bilateral middle cerebral arteries. The narrowing progressively deteriorated as was demonstrated on longitudinal serial follow-up MR imaging. X-ray angiography performed at 51 months after radiosurgery confirmed that the cAVM was cured and a diagnosis of moyamoya disease. To the best of our knowledge, this is the first case of cAVM-associated moyamoya disease that developed after radiosurgery. Given the chronological sequence of disease development and radiation dose distribution of radiosurgery, it is proposed that humoral or unknown predisposing factors, rather than direct radiation effects, are the cause of moyamoya disease associated with cAVM.