Surgical excision of an extradural intraspinal synovial cyst at the foramen magnum in a dog

A 6-year-old, female, neutered labrador retriever was presented for investigation of cervical pain. At initial presentation, pain was localised to the cervical region. No neurological deficits were observed. Computed tomography scan and magnetic resonance imaging revealed an extra-axial cyst-like lesion at the level of the foramen magnum, with extension into the caudal fossa. Conservative management, which included activity restriction and a 4-week course of corticosteroids failed to resolve the clinical signs, and the cyst was eventually surgically excised. Histological examination of the sample submitted confirmed a synovial cyst. The dog recovered uneventfully after surgery and remained pain free until the last follow-up (9 months). Thus, surgical excision of an extradural intraspinal synovial cyst in a dog provided resolution of the clinical signs.