There are many different types of brain tumours. They are usually named after the type of brain cells from which they have developed. They may also be named after the area of the brain they are growing in.
Most tumours develop from the supporting cells of the brain known as the glial cells. They may be named after the type of cell that they are made up of, or after the part of the brain where they are found; such as a brain stem glioma. More than half of all primary brain tumours are gliomas.
Grading is a term that refers to how the tumour cells look under a microscope. The cells will be examined by a specialist doctor (pathologist) who will look at whether there are signs the cells are dividing, how abnormal they look, and if there are any abnormal blood vessels.
The grade gives an idea of how quickly the tumour may have developed and how fast it may grow. There are four grades: grade 1 tumours are benign and grow very slowly, whereas grade 4 tumours are malignant (cancerous) and grow faster. Sometimes grade 1 and 2 gliomas are called low-grade gliomas, and grades 3 and 4 are called high-grade gliomas. Knowing the type and grade of your tumour will help your doctors plan the best treatment for you.
Medulloblastomas are one of the most common malignant brain tumours in children, but they are rare in adults. They usually develop in the cerebellum at the back of the brain but may spread to other parts of the brain. Very occasionally, these tumours spread outside the brain to the lymph nodes or lungs.
Medulloblastoma is a type of primitive neuroectodermal tumour (PNET). PNETs develop from cells that are left over from the earliest stages of a baby′s development in the womb.
Meningiomas arise from the meninges, which are the membranes that cover the brain. They can occur in any part of the meninges over the brain or spinal cord and usually grow very slowly. There are three subtypes of meningioma:
A lymphoma is a malignant tumour of the lymphatic system, which is part of the body′s immune system and its natural defence against infection and disease. The lymphatic system is made up of organs such as bone marrow, the thymus, the spleen and lymph nodes. The lymph nodes throughout the body are connected by a network of tiny lymphatic tubes (ducts). In rare cases, lymphomas only affect the brain. They are then called primary CNS lymphomas.
The pineal gland is just below the area where the two cerebral hemispheres join together. Tumours in this part of the brain are extremely rare. They can be made up of different types of cells. Some may be slow-growing, while others may grow more quickly.
The most common tumours found in the pineal gland are germinomas; others include teratomas, pineocytomas and pineoblastomas.
Acoustic neuromas (also called vestibular schwannoma or neurilemmoma), are benign tumours that develop in the acoustic or auditory nerve, which controls hearing and balance. The nerve is covered by cells called Schwann cells. The tumour starts from these cells, so it′s also known as a schwannoma.
Acoustic neuromas are usually only found in adults and are more common in people who have a genetic condition called neurofibromatosis type 2 (NF2).
This is a rare type of tumour that develops from the cells that line the blood vessels. Haemangioblastomas are benign and grow slowly. It may take several years for symptoms to appear.
Pituitary tumours are benign and are also called pituitary adenomas. Symptoms often appear as disturbances in vision or hormone levels.
Spinal tumours often cause symptoms by pressing on the spinal nerves. These symptoms may include numbness, tingling, leg or arm weakness, and pain in the back, neck and limbs.
Sometimes a tumour in the lower part of the spinal cord can lead to loss of control of the bladder or bowel (incontinence).
Gliomas, meningiomas, schwannomas, neurofibromas and haemangioblastomas can all affect the spinal cord as well as the brain.