Spinal tumors account for a small percentage of all tumors of the central nervous system. They appear in three forms. . Primary spinal tumors These tumors, which are quite rare, occur in the vertebral column and grow either from the bone or disc elements of the spine. They typically occur in younger adults, and they usually grow slowly. Osteogenic sarcoma (osteosarcoma) is the most common malignant bone tumor. . Metastatic spinal tumors Most spinal tumors have metastasized (spread) from cancer in another area of the body. . Intradural-extramedullary tumors Intradural-extramedullary tumors grow within the spinal canal, under the membrane that covers the spinal cord but outside of the nerves. These tumors usually are benign and slow growing.