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Health condition · Clinically reviewed

Embryonal tumours, medulloblastoma, ATRT and ETMR explained for families.

Aggressive but increasingly treatable childhood brain tumours. Modern care combines molecular subgrouping, maximal safe surgery, proton radiotherapy and risk-adapted chemotherapy in specialist UK centres.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a UK-registered clinician before publication.

  • 02

    Sourced from guidance

    Checked against WHO 2021 CNS classification, NICE, RCR and SIOP Europe standards you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK paediatric neuro-oncology practice including molecular subgrouping, proton therapy and risk-adapted chemotherapy.

Key facts

Embryonal tumours at a glance.

The essentials for families, in plain English - what they are, who is affected and how they are treated in modern UK paediatric neuro-oncology.

  • What they are

    A group of aggressive malignant tumours arising from embryonic or undifferentiated cells in the central nervous system, defined by the WHO 2021 classification.

  • Who is affected

    Predominantly children, with a median age of around 5 to 9 years. Some subtypes (ATRT, ETMR) mainly affect infants and children under three.

  • Main types

    Medulloblastoma, atypical teratoid/rhabdoid tumour (ATRT), embryonal tumour with multilayered rosettes (ETMR), medulloepithelioma, CNS neuroblastoma and CNS tumour with BCOR ITD.

  • How they present

    Hydrocephalus and raised intracranial pressure - morning headache, vomiting, cerebellar ataxia, cranial nerve signs, seizures, developmental regression.

  • How we treat

    Specialist paediatric neuro-oncology MDT care: maximal safe surgery, craniospinal radiotherapy (often proton beam) and intensive risk-adapted chemotherapy.

  • Why molecular matters

    Medulloblastoma subgroups (WNT, SHH, Group 3, Group 4), SMARCB1/A4 loss in ATRT and C19MC amplification in ETMR each drive treatment stratification and prognosis.

Why this guide matters

Modern childhood neuro-oncology has changed the picture.

Molecular subgrouping, proton therapy and risk-adapted chemotherapy have improved outcomes and reduced late effects. These are the three ideas that shape everything that follows.

  • Molecular diagnosis matters

    Medulloblastoma subgroup, SMARCB1/A4 status in ATRT and C19MC amplification in ETMR now sit alongside microscopy - they change treatment intensity and prognosis.

  • Protons protect the brain

    Where craniospinal irradiation is needed, proton beam therapy at UCLH or The Christie reduces dose to developing brain, cochlea and heart and lowers late effects.

  • Risk-adapted, not one-size

    Standard-risk children can safely receive less-intense treatment. High-risk disease gets intensified chemotherapy and, in ATRT and ETMR, high-dose regimens with stem cell rescue.

How the diagnosis is made

From first symptoms to a specialist MDT plan.

The steps a UK paediatric neuro-oncology service will normally follow, in order - so families know what to expect and why each test matters.

  1. 01

    Recognising

    Recognition and urgent referral

    Persistent morning headache and vomiting, new ataxia, cranial nerve signs, seizures or developmental regression in a child - urgent CNS imaging under HeadSmart criteria.

  2. 02

    Recognising

    MRI brain and spine with gadolinium

    The imaging standard. Whole-neuraxis MRI is essential to identify the primary tumour and any leptomeningeal (drop) metastases before surgery where possible.

  3. 03

    Recognising

    Neurosurgical assessment

    Maximal safe resection is prognostic. Emergency management of hydrocephalus may be needed - external ventricular drain, endoscopic third ventriculostomy or VP shunt.

  4. 04

    Confirming

    Histopathology and molecular testing

    Specialist paediatric neuropathology on biopsy or resection: subgroup for medulloblastoma, SMARCB1/SMARCA4 (INI1/BRG1) for ATRT, C19MC for ETMR, MYC/MYCN and TP53 status.

  5. 05

    Confirming

    CSF cytology for staging

    Lumbar puncture after imaging, once safe (no obstructing mass or dangerous pressure), to look for tumour cells - important for risk stratification.

  6. 06

    Confirming

    Germline and cancer-predisposition testing

    Consider TP53 (Li-Fraumeni), SMARCB1 (rhabdoid predisposition), RB1, APC (Turcot), NF and other genes. Guides family screening as well as the childs treatment.

  7. 07

    Planning

    Paediatric neuro-oncology MDT

    Care is planned in one of the specialist commissioned UK centres - Great Ormond Street, Alder Hey, Birmingham Childrens, Bristol, Newcastle, Cambridge, Leeds, Manchester, Nottingham, Sheffield, Royal Marsden Sutton.

Typical timeline: from first imaging to a full MDT plan within days to a few weeks at a specialist centre.

Symptoms

What families and clinicians look for.

Most embryonal tumours cause raised intracranial pressure and cerebellar or brainstem signs. HeadSmart criteria in the UK are designed to shorten time to diagnosis.

  • Morning headache and vomiting

    The classic sign of raised intracranial pressure from hydrocephalus - often worse on waking and eased by vomiting.

  • Cerebellar ataxia

    Unsteady gait, clumsiness, dysmetria and intention tremor - typical of posterior-fossa tumours such as medulloblastoma.

  • Nystagmus and eye movement change

    New squint, sixth-nerve palsy or nystagmus can reflect brainstem or cerebellar involvement, or raised pressure.

  • Reduced consciousness and irritability

    Drowsiness, personality change or unusual irritability in a young child needs urgent assessment.

  • Seizures and focal neurology

    New seizures, limb weakness or sensory change point to a supratentorial or invasive lesion.

  • Developmental regression

    Loss of milestones, delayed speech or new learning difficulty in a previously well child is a red-flag symptom.

  • Failure to thrive and growth issues

    Poor weight gain, short stature or endocrine features can accompany midline and hypothalamic disease.

  • Red flag - papilloedema

    Swollen optic discs on fundoscopy signal raised intracranial pressure - a neurosurgical emergency until proven otherwise.

Treatment

How embryonal tumours are treated in the UK.

Care is delivered by specialist commissioned paediatric neuro-oncology MDTs. The pillars are surgery, radiotherapy (proton where possible), chemotherapy and, in some subtypes, high-dose therapy with stem cell rescue.

  • Maximal safe neurosurgery

    The first step for most children - resection removes as much tumour as is safely possible and provides tissue for molecular diagnosis. Extent of resection is prognostic.

  • Craniospinal radiotherapy

    Standard for medulloblastoma and other embryonal tumours in older children. Dose is risk-adapted - reduced-dose CSI is used for standard-risk WNT-driven disease.

  • Proton beam therapy

    Increasingly the preferred radiation modality for children - delivered at UCLH and The Christie. It spares developing brain, hippocampus, cochlea and heart and reduces late effects.

  • Standard-risk chemotherapy

    For standard-risk medulloblastoma: vincristine, cisplatin, cyclophosphamide, lomustine and procarbazine along the lines of SIOP PNET-5 and COG ACNS0331.

  • Intensified chemotherapy

    For high-risk medulloblastoma, ATRT and ETMR: carboplatin, cisplatin, cyclophosphamide, vincristine and etoposide, often followed by high-dose consolidation.

  • Autologous stem cell rescue

    High-dose chemotherapy with autologous stem cell rescue is used for ATRT, ETMR and very young children with medulloblastoma to avoid or delay radiotherapy.

  • Targeted and trial therapy

    Smoothened inhibitors (vismodegib, sonidegib) in SHH medulloblastoma, EZH2 inhibitors and other subgroup-specific drugs are available through clinical trials.

  • Supportive and survivorship care

    Hydrocephalus management, ototoxicity monitoring, endocrine and growth-hormone replacement, neuropsychology, education, rehabilitation and long-term follow-up.

What this guide is based on

The sources behind every claim on this page.

UK national guidance, international classification and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your childs paediatric neuro-oncology team knows their history, imaging and pathology and can tell you which parts apply to your family. If in doubt, contact them.

  • WHO Classification of Tumours of the Central Nervous System, 5th edition (2021).

  • NICE guidance on brain tumours (primary) and metastatic brain tumours in adults and children.

  • SIOP Europe (SIOPE) Brain Tumour Group protocols including PNET-5 medulloblastoma and ATRT-2020.

  • Royal College of Radiologists (RCR) guidance on paediatric radiotherapy and proton beam therapy referral criteria (UCLH and The Christie).

  • Childrens Cancer and Leukaemia Group (CCLG) standards for paediatric neuro-oncology in the UK.

Red flags

When to act quickly.

Symptoms that warrant urgent same-day paediatric assessment, and situations where the specialist team must be contacted straight away.

  • Rapidly falling consciousness

    A drowsy, unrousable child with a suspected posterior-fossa mass is a neurosurgical emergency - call 999 and get to a paediatric neurosurgery centre.

  • Papilloedema and vision loss

    Sustained raised intracranial pressure threatens sight and life. Urgent imaging and CSF diversion are needed.

  • New seizures in a child

    Any first afebrile seizure warrants prompt paediatric assessment and imaging - especially with focal neurology or headache.

  • Very young child (<3 years)

    ATRT and ETMR occur in infants and toddlers where radiotherapy is limited by developmental toxicity - urgent specialist input is essential.

  • Family history of Li-Fraumeni or rhabdoid predisposition

    A germline TP53 or SMARCB1 change changes both treatment (radiation caution) and cascade family screening.

  • Persistent morning vomiting

    Repeated early-morning vomiting in a child - especially with headache or ataxia - should prompt imaging, not just antiemetics.

  • Loss of milestones

    Regression of previously acquired skills is never normal and warrants urgent paediatric review.

  • Progressive gait disturbance

    Worsening ataxia or unsteadiness over days to weeks needs same-day neurological assessment.

  • Post-treatment red flags

    New headache, seizure, hormonal symptoms, unexplained fatigue or lump in a survivor - contact the treating team promptly.

Living with it

A long journey, supported at every step.

Treatment for an embryonal tumour is intense, but so is the wraparound care. Four themes make the biggest difference for children and their families.

A quiet reminder

Survivorship starts on day one.

Cognitive, endocrine and hearing follow-up is planned from the very first treatment cycle, not added on years later.

  1. 01 Team

    Care is a team effort

    Paediatric oncologist, neurosurgeon, radiation oncologist, specialist nurse, neuropsychologist and endocrinologist all play a part. Ask who your key contact is.

  2. 02 Late effects

    Plan for the long haul

    Hearing, endocrine, growth, cognition, cardiac and fertility can all be affected by treatment - structured survivorship follow-up matters as much as the acute treatment.

  3. 03 Support

    You are not alone

    Teenage Cancer Trust, Young Lives vs Cancer (formerly CLIC Sargent), The Brain Tumour Charity and Children with Cancer UK all offer practical and emotional support.

  4. 04 Family

    Genetic counselling counts

    Where a germline predisposition is found, cascade testing lets siblings and parents be screened and protected too.

Frequently asked

Questions families ask.

Straightforward answers on subtypes, molecular testing, proton therapy and long-term follow-up.

  • What are embryonal tumours of the central nervous system?

    They are a group of aggressive, high-grade malignant brain and spinal cord tumours that arise from embryonic or undifferentiated cells. The WHO 2021 classification recognises several types including medulloblastoma, atypical teratoid/rhabdoid tumour (ATRT), embryonal tumour with multilayered rosettes (ETMR), medulloepithelioma, CNS neuroblastoma and CNS tumour with BCOR internal tandem duplication.

  • Who gets them and at what age?

    They are predominantly childhood tumours, with a median age of around five to nine years. Medulloblastoma is the commonest paediatric CNS malignancy. ATRT and ETMR mainly affect children under three, which shapes treatment because young brains are especially vulnerable to radiotherapy.

  • Why does molecular subgrouping matter for medulloblastoma?

    WHO 2021 defines four medulloblastoma groups - WNT-activated (best prognosis), SHH-activated (further split by TP53 status), non-WNT/non-SHH Group 3 (highest risk, often MYC-amplified) and Group 4. Subgroup drives risk stratification, choice of chemotherapy, radiotherapy dose and eligibility for targeted therapy such as SMO inhibitors in SHH disease.

  • What role does proton beam therapy play?

    For children needing craniospinal radiotherapy, proton beam therapy is often preferred because it deposits far less dose in the developing brain, hippocampus, cochlea and heart. In the UK it is delivered at UCLH and The Christie under NHS-commissioned pathways and can substantially reduce late neurocognitive, endocrine and cardiac effects.

  • How is ATRT treated differently?

    ATRT is typically diagnosed in very young children and defined by loss of SMARCB1 (INI1) or, rarely, SMARCA4 (BRG1). Treatment is intensive multi-agent chemotherapy, often with high-dose chemotherapy and autologous stem cell rescue, and radiotherapy is used cautiously with age. Trials such as SIOPE ATRT-2020 guide current UK practice.

  • What about long-term outlook and late effects?

    Survival has improved substantially, particularly for WNT-driven medulloblastoma. Late effects - neurocognitive, endocrine, hearing, growth, fertility, cardiac and secondary cancers - remain a major concern, especially after craniospinal radiotherapy in younger children. Structured long-term survivorship follow-up in a specialist commissioned centre is essential.

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