Spinal cord medulloepithelioma in a dog.

Medulloepithelioma, an embryonal neural tumor, was diagnosed in a 6-month-old Bullmastiff. Clinical signs of incomplete, upper motor neuron, transverse myelopathy involving the hindlimbs were observed on examination. Myelography was required to identify the cause of clinical abnormality. The tumor involved the L1 spinal cord segment.