A brain tumour is a group of abnormal cells in the brain. Spinal cord tumours begin in cells of the spinal cord. Primary brain or spinal cord tumours start in the brain or spinal cord. They can be either benign (non-cancerous) or malignant (cancerous). In most parts of the body, a benign tumour is not as serious as a malignant tumour. In the brain, both benign and malignant tumours can be serious and possibly life-threatening.
Benign brain or spinal cord tumours do not contain cancer cells. They don’t invade nearby tissues, but they can press on certain parts of the brain or spinal cord, causing serious health problems.
Malignant brain or spinal cord tumours contain cancer cells. They tend to grow quickly and cause increased pressure in the brain or spinal cord. They can also spread to other parts of the brain or the spinal cord.
Cancerous tumours that start in another part of the body can spread to the brain. These are called secondary brain tumours. They may also be called metastatic brain tumours or brain metastases.
The brain and spinal cord
Together, the brain and spinal cord are known as the central nervous system (CNS). The spinal cord runs through the spine. It contains nerves that send information to and from the brain. The brain is a soft, spongy mass of tissue. It is the control centre of your body. The 3 main parts of the brain control everything your body does:
- The cerebrum is the largest part of the brain. It is made up of 2 parts, called hemispheres. The right side of your brain controls the left side of your body and the left side of your brain controls the right side of your body. Each hemisphere is divided into sections, or lobes. You use the cerebrum to see, feel, think, speak and move. The cerebrum receives messages from your senses to tell you what is going on and how to respond. It also controls thinking and memory.
- The cerebellum is under the cerebrum at the back of the brain. The cerebellum controls balance and coordination.
- The brain stem is at the bottom of the brain. It connects the brain to the spinal cord. It controls the basic body functions needed to live, including blood pressure, heartbeat, breathing and reflexes.
The brain is wrapped in 3 thin membranes, called meninges. A watery fluid called cerebrospinal fluid (CSF) fills the spaces between the meninges and cushions the brain. The brain is protected by the skull.
The brain is made up of 2 types of cells: nerve cells (neurons) and glial cells. The nerve cells form a network that carries messages back and forth between the brain and the rest of the body. Glial cells surround the nerve cells and hold them in place.
The 2 most common types of brain tumours in children are gliomas and medulloblastomas. Gliomas start in glial cells. Gliomas are not a specific type of cancer. They are the most common type of primary tumour in the central nervous system (CNS). Medulloblastomas are a type of primitive neuroectodermal tumours (PNETs). Neuroectodermal tissue normally grows and matures into nerve cells. PNETs start in neuroectodermal cells that do not develop into normal nerve tissue.
Tumours that develop in the spinal cord are rare in children. The same types of tumours that develop in the brain can occur in the spinal cord. The most common types of spinal cord tumours are gliomas.
