A tumour in the brain or spinal cord, composed of neuroglia, which is the special connective tissue that supports the nerve cells and nerve fibres (see GLIA). Low-grade malignant gliomas cause symptoms by putting pressure on surrounding tissues and organs. Highly malignant gliomas are usually invasive. Gliomas, like other space-occupying tumours in the brain, may present with headaches, seizures, neurological symptoms or symptoms of mental disturbance. Treatment may include surgery, radiotherapy and chemotherapy and should be done in a specialist neurological centre.