Can multiple sclerosis be differentially diagnosed from myelomalacia due to a spinal cord injury?

The injury may have been induced by flexion and extension of a mild cervical stenosis from a disc bulge?

Clinical symptoms of either MS or cervical myelopathy for several years. Recent MRI showed plaque inside the spinal cord in the cervical spine 5mm x 10mm, and a 8mm lesion in the brain (cerebellar peduncle).

Would a spinal tap help?