Medulloblastomas/Primitive Neuroectodermal Tumours (PNET)

What are Medulloblastoma and PNET?

Medulloblastoma and primitive neuroectodermal tumour (PNET) are aggressive types of brain tumours that originate from embryonic cells in the brain. These tumours are most common in children but can also affect adults. Medulloblastomas specifically arise in the cerebellum, the part of the brain responsible for balance and coordination, while PNETs can occur in other parts of the central nervous system. Both are classified as Grade IV tumours due to their rapid growth and tendency to spread within the brain and spinal cord.

Types of Medulloblastoma and PNET

Medulloblastomas are further categorised based on their molecular and genetic characteristics, which influence prognosis and treatment strategies:

1. WNT-Activated Medulloblastoma: Known for its favourable prognosis, this type responds well to treatment.

2. SHH-Activated Medulloblastoma: Associated with mutations in the Sonic Hedgehog signalling pathway, it has varying prognoses depending on patient age.

3. Group 3 Medulloblastoma: Typically aggressive and associated with a poorer prognosis.

4. Group 4 Medulloblastoma: The most common subtype, with intermediate outcomes.

PNETs, although similar in their embryonic origin, can occur in various locations and are identified based on histological characteristics.

Symptoms of Medulloblastoma and PNET

Symptoms are typically related to increased intracranial pressure and the tumour's location in the brain. Common symptoms include:

• Persistent and worsening headaches, especially in the morning

• Nausea and vomiting

• Difficulty with balance and coordination

• Visual disturbances, such as double vision

• Behavioural or cognitive changes

• Weakness or numbness in the arms or legs

• Seizures (less common)

Diagnosis and Treatment Options

Diagnosis: Medulloblastoma and PNET are diagnosed through a combination of:

• Imaging Tests: MRI and CT scans are used to identify the tumour’s location and size.

• Biopsy: Essential for confirming the tumour type and guiding treatment.

• Lumbar Puncture: To detect cancerous cells in the cerebrospinal fluid, indicating spread.

Treatment: Treatment is intensive and involves a multimodal approach:

1. Surgery:

   • The primary treatment to remove as much of the tumour as possible while minimising damage to surrounding brain tissue.

2. Radiotherapy:

   • Commonly used after surgery to target residual cancer cells. In children, craniospinal irradiation may be required to address potential tumour spread.

3. Chemotherapy:

   • Often used in combination with radiotherapy to improve outcomes, particularly in high-risk cases.

4. Targeted Therapy and Clinical Trials:

   • Newer treatments focusing on specific genetic mutations or pathways are under investigation and may be available through clinical trials.

Living with Medulloblastoma and PNET in Singapore

At Singapore Brain Spine Centre, we provide comprehensive care for patients with medulloblastoma and PNET. Our team of experts uses advanced diagnostic techniques and personalised treatment plans to deliver the best possible outcomes while ensuring adherence to ethical standards set by the Healthcare Services Act​​​.

Conclusion

Medulloblastoma and PNET are challenging tumours that require prompt and expert care. Early diagnosis and a multidisciplinary treatment approach are essential for improving outcomes and quality of life. If you or a loved one experiences persistent neurological symptoms seek immediate evaluation. Visit the Singapore Brain Spine Nerves Center for specialised care and support.