Brain tumours are collections of cells within your brain that are growing in an abnormal way. There are two main groups - benign or malignant. Benign tumours are slow-growing, non-cancerous growths which are less likely to return after treatment than malignant tumours. In contrast malignant tumours are fast-growing and are cancerous. Malignant tumours can spread to or from elsewhere (secondaries) whereas benign tumours do not spread, other than getting slowly larger. Around half of brain tumours are benign and half cancerous, and they can occur at any age although they get more common the older you are.
Symptoms are variable depending on where the tumour is growing. People are frequently scared by headaches, but in fact this is by no means the only or main symptom of a tumour.
However headaches can of course be a symptom, but they are usually of an abnormal type - increasingly severe and frequent. They may be associated with vomiting from no obvious cause. Other symptoms may be a convulsion (fit) in someone who hasn't had convulsions before, changes in personality, drowsiness, visual or hearing problems, or problems with speech or balance, or progressive weakness of paralysis of a limb.
As stated brain tumours can be benign or cancerous (and the latter primary or secondary). They are named after the type of tissue that they develop from such as meningiomas (arising from the meninges), gliomas (from glial cells), acoustic neuromas (from the accoustic nerve) etc.
The direct cause of most brain tumours is not known, but there are certain risk factors: age, previous cancers, radiation, family history, and HIV infection all increase the risk of developing a brain tumour.
The treatment of a brain tumour depends on the location and size of the tumour. Some are amenable to surgery, such as meningiomas as they are on the surface of the brain, or pituitary adenomas because you can operate on them easily up through the back of the nose, whereas other tumours will be deep within the brain and the neurosurgeon will have to weigh-up the risks of damage to healthy tissue trying to reach the tumour.
In some cases surgery is not able to remove all of the tumour and subsequent radiation or chemotherapy is needed to try and destroy the remaining tumour cells.