Any tumour that grows inside the bones of the skull is referred to as a brain tumour. Basically, any tissue can proliferate inside the skull; only the most common types of tumour are briefly discussed here. Brain tumours can be roughly divided into benign (non-cancerous) and malignant (cancerous) formations.
However, when it comes to the brain, ‘benign’ certainly does not mean that there is no danger. Brain tumours can press on other surrounding structures and put greater pressure on vital brain centres, because the surrounding bones cannot move if the volume inside increases.
In most cases, the cause of brain tumours is not known. Whether hereditary and external factors have an influence is still being debated. For example, it still cannot be proved that electromagnetic fields from mobile phones or high-voltage power lines affect the development of brain tumours. Only the cause of metastatic brain tumours is known – cancer cells spreading to the brain from another malignant tumour in the body via the bloodstream.
Most symptoms caused by brain tumours do not clearly point to a brain tumour. The symptoms depend on the location, size and growth speed of the tumour.
The most common symptoms are:
- Nausea, vomiting and slow pulse are potentially signs of increased cranial pressure
- Seizures (similar to epileptic fits)
- Psychological changes (apathy, irritability, memory disorders)
- Depending on the type and localisation of the tumour, there may also be muscular weakness and paralysis, hearing difficulties, visual disorders, difficulty swallowing or speech impairment
Individual tumour types are described below according to their special features:
Glioma: A type of tumor that forms in the brain or spinal cord, and begins in the supportive cells that surround and aid the functioning of nerve cells. How the tumor grows and is treated depends on the type of supportive cells it started from.
- Glioblastoma: a highly malignant tumour that grows very rapidly in the surrounding area. Paralysis and speech impairment are evident after only a few weeks or months. Survival after diagnosis is often only a matter of months or a few years.
- Ependymoma and medulloblastoma: these brain tumours typically occur in children and young people. Ependymomas often create intracranial pressure (resulting in headaches, vomiting, slow pulse). Patients can live for several years more after diagnosis.
- Meningioma: these are basically benign tumours but they can displace surrounding structures as a result of rapid growth. If meningiomas do not grow or only grow slowly, there may be no symptoms.
- Pituitary tumour: the pituitary gland (hypophysis) produces hormones. Typical symptoms of pituitary tumours are, first, hormonal disturbances (growth disorders, fatigue, thin and wrinkled skin, erectile dysfunction). There are also often visual disorders (blind spots). Pituitary tumours mainly present between the ages of 30 and 50.
- Neurinoma: the tumour usually originates in the Schwann cells of the eighth cranial nerve (acoustic neurinoma). Typical symptoms are progressive hearing loss, tinnitus, loss of balance and facial paralysis.
- Investigating medical history, taking symptoms into account
- In-depth neurological examination
- Lab tests to exclude other conditions
- Imaging of the skull and brain (computed tomography or MRI)
- Potentially, measurement of brain waves (EEG = electroencephalography)
- Potentially, sampling cerebrospinal fluid from the spinal cord canal (lumbar puncture or spinal tap)
Treatment is based on the type of tumour, size and localisation. Benign brain tumours (meningiomas or neurinomas) can be surgically removed, which generally means the patient recovers. Malignant tumours, and particularly those located in vital centres, have a poor prognosis.
There are basically three possible treatment types:
The difficulty lies in differentiating between tumour tissue and healthy tissue during the procedure. Modern techniques do enable minimal damage to healthy tissue surrounding the tumour (dyeing techniques, computer-supported operations, operations on patients who are awake).
Some brain tumours respond well to radiotherapy. This can either be applied externally, through the skin, or a small source of radiation is surgically inserted in the tumour and destroys it from inside.
Chemotherapy can take various forms, including tablets or infusions. Side effects of chemotherapy are common.
Cerebral pressure can be lowered using anti-inflammatory medication (cortisone).