A spinal cord tumor may be either a cancerous or noncancerous lesion in the spinal cord that grows between the membranes covering the spinal cord or in the spinal canal. A tumor here can compress the spinal cord or its nerve roots, so even a noncancerous growth may be disabling unless it's properly treated.

The spinal cord contains bundles of nerves that carry messages between the brain and the body. Because the spinal cord is encased in bone, any tumor that grows on or near it can press on the nerves, interfering with this brain-to-body communication. These tumors are fairly rare; about 10,000 Americans develop spinal cord growths each year, and about 40% of them are cancerous.

Newly-formed tumors that originate in the spinal cord are unusual, especially among children and the elderly. More typically, tumors start to grow elsewhere in the body and move through...