Anatomical classification of spinal tumors

Spinal cord tumors are identified by their location and the progression of their growth.

Intradural tumors
1. An abnormal mass directly within the spinal cord, typical of a tumor that either started within the cord (i.e., astrocytoma) or spread to the cord from a cancer elsewhere in the body.
2. An abnormal mass that developed from the fibrous membranes that normally surround the spinal cord, typical of a meningioma.

Extradural tumors
3a. An abnormal mass originating outside the spinal column, but close enough to potentially compress the nerve roots or blood vessels exiting the spinal column.
3b. An abnormal mass growing within the vertebral bone, that may then invade the spinal canal and its contents, or weaken the spinal column. This pattern is typical of cancers that commonly spread through the blood stream to the bone, such as those from the breast, lung or prostate.
3c. An abnormal mass that starts in the small openings between the vertebrae, where the nerve roots exit. This growth would be typical of a tumor originating directly from a nerve root, such as a schwannoma or neurofibroma.