Spinal tumors—whether they're primary or secondary tumors—are caused by abnormal cell growth.

In primary spinal tumors (tumors that originate in the spine), researchers aren't sure what causes the cells to grow abnormally. For some cases, it may be related to radiation exposure or chemicals that cause cancer; it's possible that environment plays a role. Genetics may also play a role: for example, neurofibromatosis is a hereditary disorder that involves tumors on or near the spinal nerves.

For the majority of cases of primary spinal tumors, though, the medical community isn't sure what causes primary tumors.

Secondary spinal tumors are caused by cancer that has spread from another part of the body. This spreading is called metastasis.