A 4-year-old, male Bernese mountain dog was evaluated for a 1-year history of right hemiparesis. Computed tomography revealed a large hypoattenuating mass severely deforming the C5 vertebral arch, invading the C6 spinal canal, and causing spinal cord compression. The signal characteristics of magnetic resonance imaging indicated a lesion composed of adipose tissue. The mass was removed via right hemilaminectomy, and histopathological examination confirmed it was an infiltrative lipoma. The compressive lesion remained unresolved, so the dog underwent a second operation, after which he regained some ambulatory function. Although postoperative adjunctive radiation therapy was performed, the dog died 201 days after the first operation.