A case of progressive brainstem syndrome secondary to vertebral artery (VA) dolichoectasia is reported. The patient presented with partial bilateral abduction paralysis, which progressed to quadriparesis, ataxia, and areflexia. The initial diagnosis was stroke, but because of the patient's deterioration, a diagnosis of Miller-Fisher syndrome was made. Neuroimages obtained at that time revealed an ectatic left VA with minimal cervicomedullary compression. The patient continued to deteriorate despite medical management. Follow-up imaging demonstrated worsened cervicomedullary compression. An emergency posterior fossa neurovascular decompression was performed using a Gore-Tex sling and resulted in mild neurological improvement. This case emphasizes that early recognition and surgical intervention to prevent progressive neurological sequelae are crucial in symptomatic VA dolichoectasia.