Brain stem tumours (brain stem glioma) are those tumours in the part of the brain that connects to the spinal cord. It is a type of Central nervous system tumour. Surgery for brain stem tumours involves removal of the tumours and some surrounding healthy tissue during a surgical operation. Surgery is used to treat brain stem tumours only when the tumour looks focal upon doing an MRI scan, i.e. it shows that it is possible to remove the tumour without damaging the brain.