Rare mixed tumors of the brain and rarely the spinal cord which contain malignant neuroectodermal (glial) and mesenchymal components, including spindle-shaped fibrosarcoma cells. These tumors are highly aggressive and present primarily in adults as rapidly expanding mass lesions. They may arise in tissue that has been previously irradiated. (From Br j neurosurg 1995 Apr;9(2):171-8) [MeSH]