12-year-old right handed male woke up with right arm “soreness” which rapidly progressed to paresthesias and weakness of entire right arm and leg. Neurological examination showed hypophonia, hemiplegia on right side, 3-4/5 strength on left side, patchy sensory loss, brisk reflexes and ankle clonus suggestive of high spinal cord lesion. Neuroaxis MRI with MRA showed cervical cord expansion at C4 with ovoid cystic-appearing lesion, and contrast enhancement within cervical cord from C1 to C7. Prominent vessels noted along the cervical cord.

While initially thought to be an intra-axial tumor, abnormal vasculature suggested underlying vascular malformation. Spinal angiogram confirmed type II (intramedullary) AVM arising from left vertebral artery with prenidal and intranidal aneurysms, which were embolized with Onyx 18. Chest and abdomen imaging did not show other AVMs. Customized genetic testing panel for vascular malformations was negative. 

The patient had a prolonged PICU stay with tracheostomy and gastrostomy tube placement, and was eventually discharged to inpatient rehabilitation, where he was able to be decannulated. At 3 month follow up, he continued to show functional recovery with nearly full strength on the left and improving hemiparesis on right. He was also able to stand independently and take some unassisted steps.