What is a choroid plexus tumour?
Choroid plexus tumours develop from a type of brain tissue called the “choroid plexus.” This tissue lines a part of the ventricles (hollow spaces) in the centre of the brain and produces cerebrospinal fluid (CSF fluid).
What is cerebrospinal fluid (CSF fluid)?
CSF fluid is a clear, colourless liquid that transports nutrients and provides protection due to its cushioning properties. The fluid flows within the ventricles of the brain and spinal cord, and between two of the meninges, which are thin layers of tissue that cover and protect the brain and spinal cord.
Where do choroid plexus brain tumours occur?
In very young children, these tumours tend to be found in the lateral or third ventricles (hollow spaces) within the brain.
For people aged 20 to 35 years, choroid plexus tumours of the fourth ventricle and cerebellopontine angle tumours (the angle between the cerebrum and the pons of the brain stem) are more common.
For all other ages, there is no clear pattern to indicate where these tumours are most likely to occur within the ventricles of the brain.
What age groups can get choroid plexus brain tumours?
Choroid plexus tumours can be diagnosed in both children and adults, but are most commonly discovered in children, often before they reach their first birthday.
How common are choroid plexus brain tumours?
- This group of tumours is responsible for approximately 10-20% of all brain tumours diagnosed in children during their first year of life.
- They represent around 2-5% of tumours found in children under the age of 18.
- Choroid plexus tumours appear more often in females than males, though the reasons for this are not yet clear.
What do choroid plexus brain tumour grades mean?
All brain tumours are graded with reference to the guidelines published by the World Health Organisation (WHO).
Grade 1 (WHO I) choroid plexus papilloma tumours are classified as low-grade (slow-growing), benign brain tumours. They tend not to grow back if they can be completely removed by neurosurgery.
Grade 2 (WHO II) atypical choroid plexus papilloma tumours are classified as low-grade (slow-growing) brain tumours, but are more likely to return after having been removed than a grade 1 tumour.
Grade 3 (WHO III) choroid plexus carcinoma tumours are classified as high-grade tumours, which unfortunately are a malignant form of cancer that tend to spread into nearby areas of brain tissue or more extensively into the spine, carried by the CSF fluid. However, they are unable to spread outside the brain and spinal cord.
What is the prognosis for choroid plexus brain tumours?
Due to the rarity of this disease, it is difficult to establish a clear prognosis for each grade of choroid plexus tumour. Each patient will therefore be treated on an individual basis.
Symptoms of choroid plexus brain tumours
The most common symptom is headaches. This symptom is caused by hydrocephalus, the build-up of fluid in the brain, because these tumours form within brain tissue called the “choroid plexus” that produces cerebrospinal fluid (CSF), so they can alter the production of this fluid as well as causing symptoms due to their mass.
Other symptoms may include:
- Nausea and vomiting
- Abnormal eye movements
- Blurred or double vision
- A strong desire to sleep
- Trouble with walking
- In infants, an increase in the size of the head
What causes choroid plexus brain tumours?
These tumours are identified by certain genetic changes that can be detected in samples that are taken during a biopsy or a neurosurgical operation, but for most patients, why those genetic changes have happened is not clearly understood.
Rarely, these tumours can be caused by a genetic condition called Li-Fraumeni syndrome that can be passed down through families. This condition can be identified by a blood test that may be offered by the patient’s medical team.
Treatment for choroid plexus brain tumours
The first line of treatment would be neurosurgery, and if the tumour is completely removed then this may be the only treatment necessary.
In around 50% of patients, removing the tumour relieves the hydrocephalus (excess water in the brain). If the symptom persists, a shunt (drainage system) may be required.
Due to the majority of choroid plexus tumours being successfully treated by neurosurgery, the role of radiotherapy and chemotherapy in their treatment is still being explored, as the low numbers of patients requiring such treatment makes it challenging to run clinical trials with enough patients to draw a clear conclusion. However, they may be recommended for patients with tumours that are either not completely removed during surgery or not able to be removed due to complicating factors such as being difficult for the surgeon to access safely.
A second surgery might be recommended for tumours that grow back after neurosurgery, followed by radiotherapy and/or chemotherapy.
How will we find a cure for choroid plexus brain tumours?
Research we are funding across all of our Centres of Excellence will help towards finding a cure for a wide range of brain tumours.
Pioneering research at our Brain Tumour Research Centre of Excellence at Queen Mary University of London (QMUL) has led to the publication of a 2019 research paper providing evidence that a proportion of choroid plexus papilloma is characterised by prominent inflammation, which contributes to the growth of these tumours. The team is now exploring whether anti-inflammatory drugs may provide future treatment options for some subgroups of benign choroid plexus tumours, though this needs further laboratory-based work and human clinical trials before being successfully translated into a new treatment regime.
Our University of Plymouth Low-Grade Brain Tumour Research Centre of Excellence is Europe’s leading research institution for low-grade brain tumours. They study how and why a range of tumours develop, the role of inflammation in tumour progression, and explore promising new drug therapies.
The team of research and clinical experts at our Brain Tumour Research Centre of Excellence at Imperial College, London are studying how to influence brain tumour metabolism using a range of approaches, including the ketogenic diet.
Scientists at our Brain Tumour Research Centre of Excellence in the University of Portsmouth have developed models of the blood brain barrier that support research into drug therapies for all types and grades of brain tumours.
We also fund BRAIN UK at Southampton University, the country’s only national tissue bank providing crucial access to brain tumour samples for researchers from the archives of clinical neuroscience centres in the UK, effectively covering about 90% of the UK population, which is an essential component in the fight to find a cure for brain tumours.