Primary brain tumours start in the brain. Tumours can start in any part of the brain or related structures.
The most common types of brain tumours in adults start in the main part of the brain called the cerebrum. About a quarter of tumours start in the meninges. These are the membranes that surround and protect the brain and spinal cord. Around 1 in 10 tumours start in the glands of the brain such as the pituitary gland or pineal gland.
Secondary brain tumours are cancers that have spread to the brain from somewhere else in the body. These are called brain metastases.
Cancers of the lung, breast, kidney, stomach, bowel (colon), and melanoma skin cancer can all spread to the brain. This happens because cancer cells break away from the primary cancer and travel through the bloodstream to lodge in the brain. There they can begin to grow into new tumours.