Intracranial germ cell tumour
An intracranial germ cell tumour is a malignant (cancerous) tumour formed from primitive germ cells (the reproductive cells of the body).
These tumours mostly develop in one of two areas: around the pituitary gland and the pineal gland. They often secrete chemical substances into the blood, alpha-fetoprotein (AFP) and beta HCG (B-HCG). These can be used as tumour markers and may help with monitoring progress during treatment.
There are two main types of intracranial germ cell tumour: non-secreting germinomas and secreting germ cell tumours. They can spread to the cerebro-spinal fluid (CSF) surrounding the brain and spine. Another type of germ cell tumour which can be either benign or malignant is known as a teratoma.
Who gets an intracranial germ cell tumour?
These are very rare tumours. Fewer than ten children a year develop an intracranial germ cell tumour in the UK. Young adults can also develop intracranial germ cell tumours but they are again very rare. These types of tumours occur more commonly in Southeast Asia (especially Japan) but the reason for this is not fully understood.
Like most brain tumours, the cause of intracranial germ cell tumours is not known.
Signs and symptoms
Symptoms may be caused by the tumour blocking the flow of fluid surrounding the brain. This increases the pressure inside the brain. Symptoms may also happen as a result of direct pressure on or damage to the pituitary gland or nerves from the eyes. It also possible to develop symptoms (such as early puberty) related to the secretion of the “tumour markers”. Sometimes hormone deficiency can happen before the obvious development of a tumour.
Symptoms may include:
- headaches with nausea or vomiting
- hormone disturbances
- disturbed sleep patterns
- visual disturbance
- behavioural changes
- slow growth
- increased sensitivity to cold or heat
- early or delayed puberty
- appetite and weight variations.
If tumour has spread to the spine:
- difficulty walking
- problems with bladder and bowel control.
Tests / investigations
We will need to carry out some tests to find out as much as possible about the type, position and size of the tumour. This will help us to decide on the best treatment for your child. These tests include:
- CT scan – it is likely a CT scan of your child’s brain was the first specific test carried out at your local hospital. Although MRI scans are usually the best way of seeing the tumour and the effects of treatment, sometimes CT scans are also useful.
- MRI scans – these allow us to see the brain and spine in great detail and are used regularly to diagnose and follow the effect treatment is having on your child’s tumour.
- Lumbar puncture (cerebrospinal fluid (CSF) testing) – this is carried out under a general anaesthetic about 14 days after surgery. We look for any malignant cells in the CSF. At the same time, we can monitor the levels of the tumours markers.
- Blood tests for tumour markers – these are used to find out if the tumour is secreting tumour markers.
- Ophthalmic assessment – a full assessment of your child’s vision will need to be recorded at the time of diagnosis, during and after treatment. This is painless but sometimes difficult for young children.
- Endocrine assessment – if there is evidence of the tumour pressing the hypothalamus or pituitary gland we will need a full test of your child’s hormones. This usually involves simple blood tests.
Staging is a measure of how far the tumour has spread beyond its original site. It is important to know if any tumour has spread to the spine through the CSF. The level of any secreted tumour markers can tell us how aggressive (quickly growing) the tumour is and how it may respond to treatment.