Haemangioblastoma brain tumour. Coloured magnetic resonance imaging (MRI) scan of a sagittal (side) section through the head of a 78 year old woman showing a haemangioblastoma. The tumour (pink) is seen to the right of the pons, a protrusion of nerve fibres (red) at the top of the spinal cord. The tumour is partly cystic (fluid-filled) and is affecting the left lobe of the cerebellum. Haemangioblastomas are formed from cells that line the blood vessels, are almost always benign and are usually found in the cerebellum, the area at the back of the brain that controls coordination and balance. The main symptoms, such as headaches and sight problems, arise from increased pressure within the skull. Surgery is often the main form of treatment. To see the same tumour in horizontal section see images M170/438 and M170/439.