A juvenile case of cerebellar arteriovenous malformation (AVM) with gradual onset of headache and ataxia.

An 11-year-old male was admitted because of frequent vomiting and truncal ataxia which had lasted for over one week. He had clear consciousness but slowly-progressive mild headache and ataxic gait. Cranial CT revealed a 4 cm hematoma in the right cerebellar hemisphere. Angiography showed a 2 x 2 cm nidus of a pial arteriovenous malformation (AVM) in the right hemisphere fed from the right posterior inferior cerebellar artery and draining into the inferior hemispheric vein. We performed a surgical resection of the AVM after decompression therapy to counteract the brain edema. He recovered completely without any neurological deficits. This case suggests that cerebellar hemorrhage caused by AVM should be considered as a possible diagnosis when mild symptoms of headache and ataxia proceed gradually.