Health condition
Aneurysmal bone cyst
An aneurysmal bone cyst (ABC) is a benign but locally destructive blood-filled cystic lesion, mostly of children and young adults, that expands bone from within; treatment ranges from curettage to sclerotherapy - after specialist confirmation, since its imaging twin is telangiectatic osteosarcoma.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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Presents with pain and swelling, sometimes a pathological fracture, in a long-bone metaphysis or vertebra of a patient usually under 25
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Imaging shows an expansile, "soap-bubble" lytic lesion; MRI classically reveals fluid-fluid levels from settled blood - characteristic but not exclusive
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Primary ABCs carry a USP6 gene rearrangement; secondary ABCs arise within other tumours (giant cell tumour, chondroblastoma, osteoblastoma) - and the crucial mimic, telangiectatic osteosarcoma, must be excluded by specialist biopsy
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Treatment: curettage with adjuvants and grafting is standard; percutaneous sclerotherapy (polidocanol) and selective embolisation offer less invasive routes, especially for spinal and pelvic lesions; recurrence in the first two years is a recognised risk needing follow-up
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
An ABC behaves like a slowly inflating blood-filled honeycomb: septated cavities under arterial-type pressure expand the bone’s cortex to a thin shell, threatening fracture in limbs and neurological compression when vertebrae are involved. Around a third are secondary - a cystic reaction inside another tumour - which, together with the malignant mimic telangiectatic osteosarcoma, is why every presumed ABC deserves biopsy-grade certainty before definitive treatment rather than curettage on imaging alone.
Diagnosis and treatment routes
At a bone tumour unit, the sequence is imaging review, biopsy confirming the diagnosis (and sampling any underlying lesion), then treatment matched to site: extended curettage with high-speed burring and bone grafting or cement for accessible limb lesions, repeated polidocanol sclerotherapy with cure rates rivalling surgery for many sites, and pre-operative embolisation where bleeding risk is high. Children’s growth plates and spinal stability shape technique, and surveillance imaging over about two years catches the minority that recur, which are usually retreatable by the same means. In much of the UK, a routine NHS referral to the relevant specialist clinic can take several months, whereas an initial appointment with a private consultant is typically available within around two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a specialist bone tumour unit (sarcoma centre). Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Aneurysmal bone cyst.
Quick, plain-English answers to what people ask us most.
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What is an aneurysmal bone cyst?
An aneurysmal bone cyst is a benign but locally aggressive fluid-filled lesion that develops within bone, most commonly in children and young adults, which can weaken the affected bone.
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What causes an aneurysmal bone cyst?
The exact cause is not fully understood, though it's thought to involve abnormal blood flow and pressure changes within the bone, sometimes arising alongside another underlying bone lesion.
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What are the symptoms of an aneurysmal bone cyst?
Symptoms include localised pain and swelling at the affected bone, and sometimes a pathological fracture (a break occurring through weakened bone) if the cyst has significantly thinned the bone.
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Is an aneurysmal bone cyst dangerous?
It is benign (non-cancerous) and doesn't spread to other parts of the body, but it can grow and weaken the bone significantly if untreated, occasionally causing fractures or affecting nearby growth plates in children.
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Can an aneurysmal bone cyst be cured?
Yes, treatment is usually very effective, with most cysts resolving completely after appropriate treatment, though a minority can recur and need further treatment.
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How is an aneurysmal bone cyst treated?
Treatment options include curettage (scraping out the cyst) with bone grafting, or less invasive techniques like injection of sclerosing agents, chosen based on the cyst's size, location, and the patient's age.
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How long does recovery from aneurysmal bone cyst treatment take?
Recovery varies by treatment type and cyst location, but generally takes several weeks to a few months for the bone to heal and regain strength, with follow-up imaging to confirm healing.
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Aneurysmal bone cyst vs a simple (unicameral) bone cyst — what's the difference?
A simple bone cyst is typically a single fluid-filled cavity that is generally less aggressive, while an aneurysmal bone cyst has a more complex, blood-filled, multi-chambered structure and tends to be more locally aggressive, sometimes requiring more involved treatment.
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Can an aneurysmal bone cyst come back after treatment?
Yes, recurrence occurs in a proportion of cases, particularly after less invasive treatments, which is why follow-up imaging is recommended to monitor for any signs of the cyst returning.
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When should I see a doctor about possible aneurysmal bone cyst, and how quickly can I be seen privately?
See a doctor for persistent, unexplained bone pain or swelling, particularly in a child or young adult. NHS orthopaedic referral can take several weeks, while private specialist assessment is often available within about two weeks.