A brain tumour is a mass, or lump in the brain which is caused when brain cells divide and grow in an uncontrolled way.
What causes brain cells to start growing and dividing differently from healthy cells, forming a high grade (cancerous) or low grade (benign) tumour is not yet understood.
There are over 130 different primary brain and spinal tumours which are grouped and named according to the type of cell they grow from, their location in the brain and how quickly they are likely to grow and spread.
Brain tumours include types of brain cancer, however not all brain tumours are cancerous.
Brain tumours are graded 1-4 by their behaviour such as speed of growth and how likely they are to spread. These grades are then split into low grade (1-2) and high grade (3-4), with low grade tumours defined as non-cancerous and high grade tumours as cancerous.
Around 11,000 people are diagnosed with a primary brain tumour each year. This means that 29 people in the UK are diagnosed with a brain tumour every day. It is important to note that other conditions can cause similar signs or symptoms of brain tumours, but it is important to recognise these, so you can go to your doctor if you are concerned.