Cervical Intradural/Extramedullary Intervertebral Disc Extrusion in a Dog

A 6-year-old male neutered Jack Russell Terrier presented via the emergency department for subacute progressive asymmetrical tetraparesis and cervical hyperesthesia. MRI showed T2-weighted (T2W) and T1-weighted (T1W) hypointense material, positioned dorsocaudally to the C3-4 intervertebral disc on the right ventrolateral aspect of the spinal cord, causing moderate-to-severe compression of the spinal cord. The material was sharply marginated with a pointed/sharp beak-like appearance (beak sign). On parasagittal images, two hyperintense lines appearing as a "Y" were appreciated (Y-sign). Surgical findings confirmed an intradural/extramedullary intervertebral disc extrusion (IVDE). This is the first report of a cervical intradural/extramedullary IVDE in a dog.