Background: Cerebral AVMs associated with definite or probable moyamoya disease is a very rare situation, and the association between them is unclear.
Case description: An 8-year-old boy presented with repeated transient motor weakness in the left arm and leg for 1 year. On his admission, physical examination and neuropsychological testing showed no exact neurological deficits. Magnetic resonance imaging showed a giant AVM in the right basal ganglia and thalamus. Angiography revealed occlusion of left ICA and bilateral PCA with well-developed basal collateral vessels. A giant AVM was also noticed in angiography, which was filled by basal collateral vessels from both left anterior circulation and posterior circulation. The diagnosis of unilateral moyamoya disease combined with a Spetzler-Martin grade V AVM was made. The patient was managed nonoperatively and discharged with close follow-up.
Conclusion: We present a rare case of giant AVM-associated with unilateral moyamoya disease, and giant AVM makes planning any aggressive treatments difficult.