What are Brain Tumours?

12/03/2021

Brain tumours are a mass or growth of abnormal cells inside the cranium (the part of the skull that encases the brain). There are two main groups of brains tumour: primary and metastatic. Tumours that originate from the brain’s tissue or its immediate surroundings are called primary brain tumours. Primary brain tumours can be benign or malignant. Metastatic brain tumours are tumours that originated elsewhere in the body and have spread to the brain. Metastatic brain tumours are considered malignant.

Types of Benign Brain Tumours

Benign tumours are not cancerous. They are made up of cells that are similar to normal cells. They do not invade nearby tissue or spread to other parts of the body. Even though they are not cancerous, benign brain tumours can cause a problem if they involve or compress nerves or brain tissue.

There are many types of benign brain tumours including:

  • Meningiomas – these are the most common typically benign intracranial tumour which develops within the meninges (the layer of tissue that covers the brain) of the brain.
  • Pituitary adenomas – largely benign and slow growing tumour that rarely spread to other parts of the body. Pituitary tumours can be split into two groups depending on whether they make hormones or not: non-secreting / non-functioning tumours vs secreting / functioning pituitary tumours.
  • Vestibular schwannoma (formally known as acoustic neuroma) – these benign brain tumours start in the nerve that connects the brain to the ear. They are slow growing tumours and do not spread to other parts of the body.
  • Hemangioblastomas – these are rare, slow growing brain tumours which originate in cells that line the blood vessels in the brain, spinal cord and brain stem. Most occur in the cerebellum. Some hemangioblastomas result from a rare inherited syndrome called von Hippel-Lindau syndrome: people with this syndrome have a higher risk of developing certain types of tumours including hemangioblastomas. 
  • Pilocytic astrocytomas
  • Subependymomas
  • Choroid plexus papillomas
  • Certain neuronal and mixed neuronal-glial tumours such as gangliocytoma, ganglioglioma and dysembryoplastic neuroepithelial tumours.

Types of Malignant Brain Tumours

Malignant tumours are made up of cancerous cells. They will usually grow faster than benign tumours, spread into surrounding tissues and may metastasise (spread to other parts of the body through the bloodstream or lymph system to form secondary tumours).

Metastatic brain tumours which originate from cancer elsewhere in the body and spread to the brain are the most common type of malignant brain tumour. Cancers which are most likely to spread to the brain are melanoma, lung, breast, kidney and bowel.

The most common malignant primary brain tumour is glioblastoma which is a type of glioma (tumour arising from the glia, the supporting cells of the brain).

Gliomas

Gliomas are tumours arising from the glia, the supporting cells of the brain. They are classified according to cell type, molecular genetics, grade and location. The WHO classification is the most recognised and ubiquitously used. 

Classification of glioma by cell type includes:

  • Astrocytic tumours – these tumours develop from astrocytes (cells which support neurons in the brain and spinal cord).
  • Oliodendroglial tumours – these tumours develop from oligodendroglia (cells which insulate nerve fibres in the brain and spinal cord)
  • Ependymal tumours – these are tumours that develop from ependymal cells which line the fluid filled areas of the brain (ventricles) and the spinal cord.

Classification by grade is a means of predicting biological behaviour by cellular pathology. 

  • Grade I tumours are biologically benign, slow growing and can potentially be cured by surgical excision.
  • Grade II tumours are infiltrative and, despite slow growth, almost always recur. Grade II gliomas (known as low grade gliomas) tend to progress to higher grades of malignancy, e.g. low-grade diffuse astrocytoma that transform to anaplastic astrocytoma and glioblastoma.
  • Grade III / IV tumours are malignant and fast growing and have a worse prognosis. Grade III / IV gliomas include anaplastic astrocytoma, anaplastic oligodendroglioma and glioblastoma (collectively known as high grade gliomas).  Glioblastoma is the fastest growing and most aggressive brain tumour.

Symptoms of Brain Tumours

Symptoms will vary depending on there the tumour is in the brain, however there are several symptoms commonly associated with a brain tumour:

  • headaches (these may be more severe in the morning or wake you at night);
  • seizures or convulsions;
  • personality changes;
  • difficulty thinking or speaking;
  • vision changes;
  • hearing changes such as tinnitus;
  • loss of balance or dizziness;
  • facial numbness or tingling;
  • feeling or being sick;
  •  difficulty swallowing;
  • confusion/disorientation.

Treating Tumours

Treatment of a brain tumour will depend on the type of tumour, where it is in the brain, the grade of the tumour and your general health and level of fitness. 

Initial diagnosis of a brain tumour is usually by CT or MRI scan. These tests can usually help identify the precise location and size of the tumour as well as indicate the most likely type of tumour. Sometimes further imaging or surgery is needed to confirm the type of tumour, e.g. whether it is fast or slow growing, benign or malignant.

Treatment options for brain tumours include surgery, chemotherapy, immunotherapy, radiosurgery and radiotherapy. Steroids are often used to reduce swelling caused by the tumour. Anti-epileptic medication may be used for seizures.

Contact Dr James Laban 

If you are concerned about any symptoms you have, do contact our friendly team today to book an appointment to see Dr James Laban on (02) 8320 0577. 

Dr Laban is a fellow of the Royal Australasian College of Surgeons and of the Royal College of Surgeons of England and has trained, worked, published and presented nationally and internationally. Dr Laban is a specialist cranial and neuro-oncological surgeon with expertise in treatment of benign and malignant brain tumours. Dr Laban works out of his North Shore, Northern Beaches and Central Coast consulting rooms. We are open to talk to you between the hours of 8:00am 5:00pm, Monday to Friday.