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Health condition · Clinically reviewed

Cavernous malformations, from brain to soft tissue - one family, many faces.

A slow-flow vascular family that behaves very differently depending on where it sits. Most are silent, some need a specialist plan.

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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 registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, Cavernoma Alliance UK, HHT UK and peer-reviewed vascular anomaly sources listed at the end.

  • 03

    Current for 2026

    Reflects modern UK practice across CNS cavernomas, orbital, hepatic and soft-tissue venous malformations, and mTOR-inhibitor therapy.

Key facts

Cavernous malformations at a glance.

A short orientation to a family of low-flow lesions that share a look under the microscope but behave very differently by site.

  • What they are

    A family of low-flow vascular malformations made of dilated, thin-walled sinusoidal channels. Angiographically occult and often silent for years.

  • Where they occur

    Anywhere from brain and spinal cord to orbit, liver, spleen, lung, skin and deep soft tissue. Behaviour depends heavily on site.

  • CNS lesions

    Cerebral cavernous malformation (CCM) is the classic form. Spinal cord cavernomas account for about 5 percent and are surgically demanding.

  • Hepatic lesions

    Cavernous haemangioma of the liver is the most common benign liver tumour. Usually incidental, usually left alone.

  • Orbital lesions

    Orbital cavernous haemangioma is the most common orbital tumour in adults. Presents with progressive proptosis and visual change.

  • Genetics

    Familial CCM (KRIT1, Malcavernin, PDCD10), HHT, blue rubber bleb nevus, Maffucci, Klippel-Trenaunay, Sturge-Weber and PIK3CA-related overgrowth spectrum.

Why this guide matters

One family, many organs, one MDT plan.

A companion to our cerebral cavernoma page - broadened to cover the orbit, liver, lung, spleen, skin and syndromic disease.

  • Site drives behaviour

    A hepatic haemangioma is almost always harmless. A brainstem cavernoma is anything but. Site sets the whole plan.

  • Some are syndromic

    Familial CCM, HHT, blue rubber bleb nevus, Maffucci, Klippel-Trenaunay, Sturge-Weber and PROS all include vascular lesions.

  • Specialist MDT is essential

    Sclerotherapy, sirolimus and complex surgery belong in tertiary vascular anomaly clinics with the full team on hand.

The types

Where these lesions actually sit.

A quick map of the main sites - CNS, orbital, hepatic, splenic, pulmonary, soft tissue and mixed venous-lymphatic malformations.

  • Cerebral cavernoma (CCM)

    The classic CNS lesion. Seizures, focal deficit or haemorrhage. Full detail on our dedicated cavernoma page.

  • Spinal cord cavernoma

    Rare - around 5 percent of CNS cavernomas. Myelopathy, haemorrhage and progressive deficit. Surgery is technically demanding.

  • Orbital cavernous haemangioma

    The most common orbital tumour in adults. Progressive proptosis and visual disturbance. Excision is selective.

  • Hepatic cavernous haemangioma

    The most common benign liver tumour. Usually incidental, usually observed. Resection reserved for large or symptomatic lesions.

  • Splenic cavernous haemangioma

    Usually asymptomatic and incidental. Rupture is rare. Splenectomy considered for very large or symptomatic disease.

  • Pulmonary lesions and HHT

    Often part of hereditary haemorrhagic telangiectasia. Risk of paradoxical embolism, stroke and brain abscess if untreated.

  • Soft tissue and skin

    Low-flow venous malformations, previously called cavernous haemangiomas. Cosmetic and functional problems predominate.

  • Mixed venous-lymphatic

    Overlap lesions with both venous and lymphatic components. Often need combined sclerotherapy, laser and sirolimus.

Genetic and syndromic

When cavernous lesions run in the family.

The syndromes worth recognising - because they change screening, treatment and advice for relatives.

  • Familial CCM

    Autosomal dominant with variable penetrance. Genes: CCM1 (KRIT1), CCM2 (Malcavernin) and CCM3 (PDCD10). Multiple lesions on MRI.

  • HHT

    Hereditary haemorrhagic telangiectasia (ENG, ACVRL1, SMAD4). Mucocutaneous telangiectasia plus pulmonary, hepatic and cerebral AVMs.

  • Blue rubber bleb nevus (BRBNS)

    Somatic TIE2 mosaic. Multiple cutaneous and GI venous malformations. Iron-deficiency anaemia and chronic GI bleeding are common.

  • Maffucci syndrome

    Enchondromatosis with soft-tissue haemangiomas. Increased risk of chondrosarcoma and other malignancies.

  • Klippel-Trenaunay

    Capillary, venous and lymphatic malformation with limb overgrowth. PIK3CA somatic mutations often found.

  • Sturge-Weber

    Port-wine stain in trigeminal distribution with leptomeningeal angiomatosis. Seizures, glaucoma and stroke-like episodes.

  • PROS

    PIK3CA-related overgrowth spectrum. Segmental overgrowth and vascular malformations - often responsive to targeted therapy.

  • Cascade family testing

    Once a mutation is confirmed, clinical genetics can offer testing and reassurance across the family.

  • Pregnancy and lifestyle counselling

    Some lesions grow with hormonal change. Pre-conception advice is part of the genetic assessment.

How the diagnosis is made

From first suspicion to a coordinated plan.

Imaging is the workhorse, genetics is the tie-breaker, and the vascular anomaly MDT sets the direction.

  1. 01

    Assessing

    History and full examination

    Site-directed symptoms plus a look for skin, eye or growth signs of a syndromic vascular anomaly.

  2. 02

    Assessing

    MRI as the workhorse

    Gradient-echo or susceptibility-weighted MRI is the gold standard for CNS, orbital and deep soft-tissue lesions.

  3. 03

    Assessing

    Ultrasound for abdomen

    Doppler ultrasound is usually the first look for hepatic and splenic lesions. Contrast US clarifies indeterminate cases.

  4. 04

    Confirming

    CT for staging and calcium

    CT adds value for lung lesions, calcification and pre-operative planning. Rarely diagnostic on its own.

  5. 05

    Confirming

    Angiography for AVMs only

    Cavernous malformations are angiographically occult. Catheter angiography is reserved for suspected coexisting AVMs, as in HHT.

  6. 06

    Preparing

    Genetic testing and cascade

    For familial CCM, HHT, BRBNS or PROS phenotypes, targeted panel or whole exome testing plus cascade screening of relatives.

  7. 07

    Preparing

    HHT-specific screening

    If HHT is suspected, contrast echocardiography and CT chest look for pulmonary AVMs, and MRI or US screens the liver.

Typical timeline: first MRI to MDT plan in a matter of weeks.

Symptoms

What patients actually notice.

Presentation depends entirely on where the lesion sits - from silent liver spots on ultrasound to a first seizure or slow proptosis.

  • CNS symptoms

    Seizure, focal neurology, haemorrhage or headache from cerebral or brainstem cavernomas. See our dedicated cavernoma guide.

  • Spinal cord features

    Progressive weakness, sensory change or bowel and bladder symptoms from a spinal cord cavernoma.

  • Proptosis and visual change

    Slowly progressive forward displacement of the eye, blurred vision or diplopia in orbital cavernous haemangioma.

  • Upper abdominal discomfort

    Ache or fullness under the right ribs in a large hepatic haemangioma. Most are silent.

  • Skin and soft-tissue mass

    A soft, compressible bluish swelling that fills on dependency in a low-flow venous malformation.

  • Telangiectasia and nosebleeds

    Mucocutaneous spots and recurrent epistaxis suggest HHT and prompt screening for pulmonary and hepatic AVMs.

  • Overgrowth and asymmetry

    Limb overgrowth, port-wine stain or lymphatic swelling points to a syndromic malformation such as Klippel-Trenaunay or PROS.

  • Red flag - stroke or abscess

    Paradoxical stroke, brain abscess or severe haemoptysis in HHT is an emergency and needs immediate hospital care.

Treatment

How cavernous malformations are managed.

Observation for the silent, surgery for the symptomatic, and specialist medical therapy for extensive or syndromic disease.

  • Observation with surveillance

    Small, asymptomatic hepatic, splenic and many CNS lesions are safely watched with interval imaging.

  • Microsurgical resection

    The mainstay for symptomatic accessible CNS cavernomas, growing orbital lesions and selected large hepatic or soft-tissue lesions.

  • Stereotactic radiosurgery

    Gamma knife is considered for deep, high-risk brainstem or thalamic CNS cavernomas after repeat haemorrhage.

  • Endovascular embolisation

    Interventional radiology can embolise pulmonary AVMs in HHT and can reduce vascularity before hepatic resection.

  • Sclerotherapy

    Bleomycin, sodium tetradecyl sulfate or ethanol into low-flow venous malformations reduces size and symptoms over several sessions.

  • Laser therapy

    Nd:YAG, KTP and pulsed dye laser help superficial cutaneous and mucosal venous malformations.

  • Sirolimus (mTOR inhibitor)

    Systemic sirolimus is used in extensive venous, lymphatic and PIK3CA-mutant malformations, and in blue rubber bleb nevus syndrome.

  • Specialist vascular anomaly MDT

    Great Ormond Street, Sheffield, Birmingham and Bristol run tertiary clinics combining plastics, IR, dermatology, orthopaedics, genetics and oncology.

Site-specific principles

  • CNS. Detail on our cavernoma page. Broadly - observe if silent, resect if symptomatic and accessible, radiosurgery for selected deep lesions.
  • Orbital. Surgical excision via transcranial or lateral orbitotomy when symptomatic or growing. Observation otherwise.
  • Hepatic. Observation for lesions under 5 cm and asymptomatic, with ultrasound every 6 to 12 months. Selective resection, enucleation or embolisation for large or symptomatic.
  • Soft tissue and venous malformations. Sclerotherapy, laser, compression and selective excision. Sirolimus for extensive or PIK3CA-mutant disease.
  • HHT. Cascade screening, embolisation of pulmonary AVMs, bevacizumab for hepatic disease and antibiotic prophylaxis for dental work.
  • BRBNS. Sirolimus first line for widespread disease, with surgical or endoscopic resection of problematic lesions.

What this guide is based on

The sources behind every claim on this page.

UK charities, ISSVA classification and international specialty guidance, 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 GP or vascular anomaly specialist knows your imaging and family history, and can tell you which parts apply to you.

  • Cavernoma Alliance UK. Patient information on cerebral and spinal cavernomas.

  • HHT UK and International HHT Guidelines. Screening and management of hereditary haemorrhagic telangiectasia.

  • ISSVA classification of vascular anomalies (updated).

  • European Association for the Study of the Liver (EASL). Clinical practice guidelines on benign liver tumours.

  • Royal College of Ophthalmologists. Orbital tumour guidance.

  • NICE Interventional Procedures. Sclerotherapy and sirolimus for vascular malformations.

Red flags

When to seek urgent care.

Most cavernous lesions are stable. These are the changes that shouldn’t wait for a routine appointment.

  • New neurological deficit

    Sudden weakness, speech change, severe headache or reduced consciousness suggests haemorrhage from a CNS cavernoma - call 999.

  • Acute visual loss or painful proptosis

    Rapid change in an orbital lesion needs same-day ophthalmology assessment to protect the optic nerve.

  • Massive haemoptysis in HHT

    Coughing frank blood in a person with known or suspected HHT is an emergency - risk of pulmonary AVM rupture.

  • Paradoxical stroke or brain abscess

    Untreated pulmonary AVMs let clots and bacteria bypass the lung filter. Antibiotic prophylaxis for dental work is essential.

  • Rapid growth or ulceration

    A soft-tissue vascular lesion that changes quickly, bleeds or ulcerates warrants urgent specialist review.

  • GI bleeding in BRBNS

    Iron-deficiency anaemia and melaena in blue rubber bleb nevus syndrome needs gastroenterology and haematology input.

  • Pregnancy planning

    Some lesions grow or bleed in pregnancy. HHT, large hepatic and spinal cavernomas need pre-conception counselling.

  • New seizure

    A first seizure at any age with a known cerebral cavernoma warrants urgent neurology review and safety advice on driving.

  • Family history flags

    Multiple relatives with strokes, seizures, nosebleeds or unusual birthmarks - consider syndromic disease and refer to clinical genetics.

Living with it

A specialist team, a steady plan.

Four things that make the biggest difference - one coordinating clinic, a clear surveillance schedule, sensible genetic testing and good peer support.

A quiet reminder

Most lesions stay stable for years.

The point of surveillance is not to worry - it is to notice change early enough that any decision can be a considered one.

  1. 01 Team

    One coordinating clinic

    Vascular anomalies span many specialties. A single MDT clinic keeps the plan coherent and avoids conflicting advice.

  2. 02 Surveillance

    Interval imaging matters

    Silent lesions are usually safe, but a documented schedule of MRI or ultrasound catches change early.

  3. 03 Genetics

    Test once, screen widely

    Confirming a familial mutation lets you screen relatives sensibly and avoid unnecessary tests in those who are clear.

  4. 04 Support

    Charities and peer networks

    Cavernoma Alliance UK, HHT UK, Sturge-Weber UK and AVM UK offer specialist nurses, family days and up-to-date resources.

Frequently asked

Everything we get asked about cavernous malformations.

Quick answers on imaging, genetics, surgery, sclerotherapy and sirolimus.

  • What are cavernous malformations?

    A family of low-flow vascular malformations made of dilated, thin-walled sinusoidal channels lined by endothelium. They occur in the brain, spinal cord, orbit, liver, spleen, lung, skin and soft tissue, and behave very differently by site.

  • How are they different from arteriovenous malformations?

    Cavernous malformations are low-flow, angiographically occult and rarely cause catastrophic bleeding. Arteriovenous malformations are high-flow, visible on catheter angiography and carry a higher stroke and haemorrhage risk. See our AVM and brain AVM guides for detail.

  • Are they inherited?

    Most are sporadic, but a significant minority are part of a genetic syndrome. Familial cerebral cavernous malformation (CCM1 KRIT1, CCM2 Malcavernin, CCM3 PDCD10), HHT, blue rubber bleb nevus, Maffucci, Klippel-Trenaunay, Sturge-Weber and PIK3CA-related overgrowth spectrum all include vascular lesions.

  • How is the diagnosis made?

    MRI is the gold standard for brain, spinal cord, orbital and deep soft-tissue lesions. Ultrasound is first line for hepatic and splenic lesions. CT helps with lung disease and calcification. Catheter angiography is reserved for suspected coexisting AVMs, as cavernous lesions themselves are angiographically occult.

  • When is treatment needed?

    It depends on site. Symptomatic or growing CNS, orbital and soft-tissue lesions are usually treated. Hepatic and splenic lesions are almost always observed unless very large or symptomatic. Vascular anomaly MDTs balance risk of the lesion against risk of intervention.

  • What is sirolimus and when is it used?

    Sirolimus is an oral mTOR inhibitor. It shrinks extensive venous and lymphatic malformations, PIK3CA-mutant lesions and blue rubber bleb nevus syndrome, and reduces bleeding, pain and functional impact. It is prescribed and monitored by specialist vascular anomaly clinics.

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