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Health condition · Clinically reviewed

Cavernoma, a clear guide to MRI findings, bleed risk and specialist care.

Most cavernomas are quiet. When they speak up, the answer is a considered plan, not a rushed decision. Here is how UK neuroscience teams approach it.

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 registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against Association of British Neurologists, UK neurosurgical centre protocols and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including SWI/GRE MRI, familial CCM genetic testing and specialist neurovascular management.

Key facts

Cavernoma at a glance.

The essentials, in plain English, what it is, where it sits, and how UK teams weigh up bleed risk against treatment.

  • What it is

    A cluster of abnormal thin-walled dilated capillary-like vessels in the brain or spinal cord, without normal brain tissue in between.

  • How common

    Around 1 in 200 people carry one, and many are picked up incidentally on MRI scans done for other reasons.

  • Where they sit

    Roughly 70% supratentorial cerebral, 20% brainstem (higher risk), plus cerebellum and spinal cord lesions.

  • Two forms

    Sporadic (about 80%, usually a single lesion) and familial (about 20%, autosomal dominant, often multiple lesions).

  • Familial genes

    CCM1 (KRIT1), CCM2 (Malcavernin) and CCM3 (PDCD10), including the Common Hispanic Mutation founder variant.

  • Bleed risk

    Annual haemorrhage risk is roughly 0.5 to 1.5%, higher for brainstem lesions and after a previous bleed.

Why this guide matters

Considered decisions, not knee-jerk surgery.

A cavernoma diagnosis is often unsettling. The three principles below shape how the rest of this page reads.

  • Most cavernomas are quiet

    A third to half are incidental. Watchful monitoring is a legitimate long-term plan for many patients.

  • Location changes everything

    Brainstem lesions carry higher risk and are treated in a small number of specialist UK centres, with different thresholds for surgery.

  • Familial disease is different

    Multiple lesions or a family history should trigger CCM1, CCM2 or CCM3 testing, family screening and long-term surveillance.

How the diagnosis is made

From first scan to a clear plan.

The steps a UK neurology or neurosurgery team will normally follow, so you know what to expect and why.

  1. 01

    Assessing

    History and neurological exam

    Seizures, focal deficits, headaches or an incidental scan finding, plus a careful family history for multiple lesions.

  2. 02

    Assessing

    MRI brain, the gold standard

    A classic "popcorn" lesion on T2 with mixed hyperintense and hypointense signal and a dark haemosiderin rim.

  3. 03

    Assessing

    SWI or GRE sequences

    Susceptibility-weighted imaging picks up small lesions and microcavernomas that standard sequences miss, key for familial disease.

  4. 04

    Confirming

    CT and angiography

    CT is often normal or shows subtle calcification. Catheter angiography (DSA) is typically negative because cavernomas are angiographically occult.

  5. 05

    Confirming

    Look for a co-existent DVA

    Around 1 in 5 have an associated developmental venous anomaly on the same scan. It should never be resected during surgery.

  6. 06

    Preparing

    Genetic testing when indicated

    CCM1, CCM2 and CCM3 panel testing for multiple lesions or a family history, with cascade testing offered to relatives.

  7. 07

    Preparing

    Baseline plan and MDT input

    Neuropsychology, epilepsy assessment and a personalised MRI surveillance schedule discussed at a specialist neurovascular MDT.

Typical timeline: from first MRI to a personalised long-term plan within weeks.

Symptoms

What a cavernoma can look like.

From silent MRI findings and cortical seizures to focal deficits from a brainstem bleed, and the features that mean it is time to act.

  • Seizures

    The commonest presentation for cortical lesions, seen in around 40 to 50% at some point in the illness.

  • Focal neurological deficit

    Weakness, numbness, visual change or speech disturbance from an acute bleed or growing lesion.

  • Brainstem symptoms

    Double vision, facial weakness, vertigo, swallowing trouble or limb signs, often more disabling than cortical bleeds.

  • Headache

    Often non-specific, sometimes worse around a small bleed or with associated raised pressure.

  • Incidental finding

    Between a third and a half of cavernomas are silent, discovered on MRI done for another reason such as headache or trauma.

  • Progressive deficit

    Slow accumulation of neurological signs from repeated microhaemorrhage into and around the lesion.

  • Cognitive or mood change

    Multiple familial lesions can affect memory, concentration and mood over time.

  • Red flag, acute severe bleed

    Sudden severe headache, collapse or major new deficit needs 999 and urgent CT and MRI at a neuroscience centre.

Treatment

How cavernoma is managed in the UK.

Watchful observation for most, targeted microsurgery for the right lesions, and radiosurgery reserved for a small subset of deep inoperable disease.

  • Watchful observation

    Most incidental and asymptomatic lesions are safely monitored with serial MRI, patient education and red-flag advice.

  • Microsurgical resection

    Considered for accessible symptomatic lesions, recurrent bleeds, intractable epilepsy or progressive deficit, in specialist UK neurosurgical centres.

  • Brainstem surgery

    Highly specialist and higher risk, reserved for recurrent haemorrhage or major deficit, using safe entry zones defined on preoperative imaging.

  • Stereotactic radiosurgery

    Gamma Knife or CyberKnife for selected deep inoperable brainstem lesions with recurrent bleeds. Controversial, with limited evidence.

  • Antiepileptic drugs

    Levetiracetam or lamotrigine first-line for cavernoma-related epilepsy, optimised before considering surgery for refractory seizures.

  • Epilepsy surgery

    For drug-resistant seizures, planned with video EEG and often combined with lesion resection at an epilepsy surgery centre.

  • Vascular risk management

    Blood pressure control, smoking cessation, and avoiding anticoagulants where clinically possible to reduce bleed risk.

  • Familial care pathway

    Cascade genetic testing, baseline and surveillance MRI, reproductive counselling and links to Cavernoma Alliance UK for peer support.

For selected deep inoperable lesions, our team can talk you through Gamma Knife radiosurgery and how it sits alongside surgical options.

What this guide is based on

The sources behind every claim on this page.

UK neuroscience centre protocols, specialist society guidance and peer-reviewed evidence, current at the time of last review.

Key references

Guidelines and cohorts we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your neurologist or neurosurgeon knows your scans and your story, and can tell you which parts apply to you. If in doubt, get seen.

  • Angioma Alliance and Cavernoma Alliance UK. Patient information and clinical resources.

  • Association of British Neurologists. Guidance on vascular malformations of the CNS.

  • Salman RA-S et al. Untreated clinical course of cerebral cavernous malformations: prospective cohort studies.

  • NHS specialist neurovascular centres, including Queen Square, King's, Cambridge, Oxford, Bristol, Newcastle and Sheffield. Local protocols.

Red flags

When a cavernoma needs urgent attention.

Most people never face an emergency, but these are the situations where waiting is not safe and prompt specialist input matters.

  • Sudden severe headache

    Thunderclap or worst-ever headache with or without new neurological signs. Call 999, needs urgent brain imaging.

  • New focal deficit

    New weakness, numbness, visual loss, double vision, speech disturbance or unsteadiness needs same-day assessment.

  • First seizure

    Any first seizure in a known cavernoma or as a new symptom needs urgent neurology review and imaging.

  • Brainstem warning signs

    Rapid onset double vision, facial weakness, swallowing or breathing trouble in a known brainstem cavernoma is a neurosurgical emergency.

  • Repeated bleeds

    A second confirmed haemorrhage significantly raises future risk and usually prompts a formal treatment discussion.

  • Pregnancy planning concerns

    Cavernoma is not an absolute contraindication to pregnancy, but any new symptoms in pregnancy need urgent obstetric and neurology input.

  • Family history plus symptoms

    Multiple relatives with cavernoma, stroke or seizures should prompt referral for genetic testing and screening MRI.

  • Anticoagulation dilemmas

    Any decision to start or stop anticoagulants or antiplatelets should involve a specialist familiar with your cavernoma.

  • Spinal cord symptoms

    New back pain with leg weakness, sensory change or bladder or bowel disturbance needs urgent spinal MRI.

Living with it

A known lesion, a life you still lead.

Four things that make the biggest difference day to day, from understanding your scan to knowing when to pick up the phone.

A quiet reminder

Preparation beats panic, every time.

A short written plan, shared with a partner or close family, turns a frightening moment into a series of clear steps.

  1. 01 Knowledge

    Know your lesion

    Understand where it sits, whether it has bled, and what your personal annual bleed risk looks like on paper.

  2. 02 Routine

    Blood pressure and lifestyle

    Well-controlled blood pressure, no smoking and moderate alcohol give your brain the best background to heal from any bleed.

  3. 03 Support

    Cavernoma Alliance UK

    Peer support, expert webinars and a family register make a real difference, especially with familial disease.

  4. 04 Escalate

    Know when to call

    A rehearsed plan for red-flag symptoms, ideally shared with family, means faster assessment when it matters.

Frequently asked

Everything we get asked about cavernoma.

Quick answers on risk, surgery, genetics and everyday life with a known lesion.

  • What is a cavernoma?

    A cavernoma, also called a cavernous malformation, cavernous angioma or cavernous haemangioma of the central nervous system, is a cluster of abnormal thin-walled dilated capillary-like vessels in the brain or spinal cord. There is no normal brain tissue inside the lesion, and it tends to leak small amounts of blood over time.

  • How dangerous is a cavernoma?

    For most people, a cavernoma will never cause a major problem. The overall annual haemorrhage risk is roughly 0.5 to 1.5%, but this rises for brainstem lesions, for lesions that have already bled, and in younger patients. Your neurologist or neurosurgeon will personalise the risk figure to your scan.

  • Do I need surgery?

    Most people do not. Surgery is usually considered for accessible symptomatic lesions, recurrent haemorrhage, drug-resistant epilepsy or progressive deficit. Brainstem surgery is highly specialist and only offered in selected cases at specialist UK neurosurgical centres.

  • What is the difference between sporadic and familial cavernoma?

    Sporadic cavernomas are usually solitary and account for around 80% of cases. Familial cavernomas are inherited in an autosomal dominant pattern from a change in CCM1, CCM2 or CCM3, often show multiple lesions on MRI and warrant genetic testing and family screening.

  • Should my family be tested?

    If you have multiple lesions on MRI, a known familial variant, or a family history of cavernoma, stroke or seizures, cascade genetic testing is offered to first-degree relatives. Cavernoma Alliance UK supports families through this process.

  • Can I still work, drive or exercise?

    Most people continue to work and exercise normally. Driving is governed by DVLA rules, particularly after a seizure or major bleed, and needs a formal review. High-impact contact sports and heavy lifting are usually discussed on a case-by-case basis with your neurologist.

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