A case of extraosseous intradural osteosarcoma of the spine in a dog

A 9.5-year-old labrador presented with signs of progressive C1-C5 myelopathy. Magnetic resonance imaging of the cervical spine revealed a broad-based, jagged and partially ill-defined intradural mass lesion at the level of C3-C4 cervical vertebra. Decompressive spinal surgery was performed and the removed mass was sent for histopathological examination that identified an intradural extraosseous osteosarcoma. This very rare canine spinal tumour appears to arise predominantly in the cervical spine and occurs with no predisposing factors. It should be considered as a differential diagnosis for spinal tumours.