Brain tumour. Coloured X-ray of a section through the head of a 46-year-old patient, showing a an increased number of blood vessels (bright lines) supplying a meningioma in the region of the parietal and occipital lobes. Meningiomas are tumours arising from the meninges - the membranes that surround the brain and spinal cord of the central nervous system (CNS). They are usually benign (non-cancerous) but a small number are cancerous.