Abstract
A 10-month-old， Flat-Coated Retriever presented with difficulty walking associated with a stagger. A neurologicaｌ examination revealed a loss of proprioception of the hindlimb and hypermetria. An MRI and myelography showed a bulbous expansion of the subarachnoid space at the cranial C3 position，consistent with diagnosis of an arachnoid cyst. Marsupialization surgery of the arachnoid cyst was performed. Disappearance of the arachnoid cyst and improvement in spinal compression were confirmed through post-surgical MRI. The dog in this case had an uncomplicated postoperative course with no recurrence in the 36 months following surgery.
