Vertebral Haemangioma

Vertebral haemangioma is a benign vascular lesion of bone and the most common benign tumour of the spine. It is overwhelmingly silent, usually discovered by accident on imaging performed for unrelated back pain or trauma. Only a tiny fraction ever produce symptoms, and an even smaller fraction behave aggressively enough to threaten the spinal cord.

The spectrum. For the exam, the single most useful concept is the spectrum. At one end is the typical fatty incidental lesion, which needs nothing more than recognition and reassurance; at the other is the aggressive lesion with epidural extension and cord compression, which needs a coordinated vascular and surgical plan. Everything else, including the painful but neurologically intact lesion, sits in between.

Common lesion, rare problem. The judgement being tested is which lesion to leave alone, which to treat for pain, and which to take to theatre for cord compression. The exam trap is to over-investigate or biopsy a classic incidental lesion.

Who. A vertebral haemangioma is present in roughly 10-12% of adults at autopsy, yet under 1% of all vertebral haemangiomas become symptomatic. Lesions are typically detected in the fourth to sixth decades, and aggressive symptomatic lesions show a female predominance.

Where. Lesions are frequently multiple within the spine.

• Thoracic - the most common site for symptomatic and aggressive lesions
• Lumbar - common, often the painful (non-aggressive) type
• Cervical - less common, but can cause early myelopathy

Macroscopic. A soft, reddish-brown, blood-filled lesion within cancellous bone. The horizontal trabeculae are replaced by vascular tissue, and the coarse vertical trabeculae that remain have thickened in compensation. These thickened struts are the structural basis of the corduroy and polka-dot signs.

Microscopic. Thin-walled, dilated capillary and cavernous vascular channels are lined by a single layer of bland endothelium, interspersed with mature adipose tissue and the thickened bony trabeculae. There is no cellular atypia and no mitotic activity: this is a benign vascular proliferation.

Why most are harmless. Behaviour tracks tissue make-up. A lesion rich in fat, with slow-flow vessels and widely spaced trabeculae, is metabolically quiet and mechanically stable, which is why the typical incidental lesion never declares itself. When vascular stroma replaces that fat, the lesion becomes more cellular, more vascular and more prone to expand, erode cortex and push into the spinal canal. This is the basis for the imaging distinction between quiescent (fatty, high T1) and aggressive (low T1) lesions.

Drivers of aggression. The change from a quiet lesion to an aggressive one is associated with increased vascular stroma at the expense of fat, expansion beyond the vertebral body, and sometimes a physiological trigger. Pregnancy is a recognised trigger, rare but classic. Increased circulating blood volume, venous engorgement of the epidural plexus and hormonal softening of vessel walls can unmask or worsen a previously silent lesion, sometimes producing rapid deficit in the third trimester.

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The most practical day-to-day classification separates lesions by their clinical behaviour, because this drives management.

Enneking benign staging. For benign bone tumours the Enneking benign staging system is used. It frames the lesion by its biological activity rather than its histological grade.

Stage 3 (aggressive) lesions with neurological deficit are the group in which total en bloc spondylectomy and other major resections have been reported.

Planning tools. For surgical planning of any spinal column tumour, two further tools are used alongside Enneking staging. Asked how you would stage a spinal haemangioma, name all three and say what each adds: Enneking for biological activity, WBB for resectability, SINS for mechanical instability.

Weinstein-Boriani-Biagini (WBB). The vertebra is divided into 12 radiating zones, like a clock face, and 5 concentric layers from paravertebral soft tissue to dura. The map shows exactly which structures the tumour occupies and guides the planning of a safe excision, in particular whether an en bloc resection is anatomically feasible.

Spinal Instability Neoplastic Score (SINS). SINS scores location, pain, bone lesion type, alignment, vertebral collapse and posterolateral involvement to grade instability. A higher score flags a mechanically unstable spine that may need stabilisation as part of treatment, even when neurology is intact.

The usual picture. By far the most common presentation is no symptoms at all. The lesion is reported as an aside on MRI or CT done for unrelated back pain or trauma, and examination is normal, with no tenderness and no deficit. The task is recognition and reassurance rather than work-up.

Axial back pain. A minority present with persistent, mechanical pain localised to the affected level, often the only symptom and without neurological signs. Other causes of back pain must be excluded before the pain is attributed to the lesion.

Neurological presentations. Expansion of the lesion can irritate a nerve root and produce a radiculopathy. An acute deficit is rare, from haemorrhage or rapid expansion.

Progressive myelopathy. Rare, and seen with aggressive lesions. Epidural extension compresses the cord, with gradual onset of leg weakness, gait disturbance or imbalance, a sensory level, and bladder or bowel change. When progressive it is a neurosurgical and oncological emergency.

Red flags. Treat a vertebral haemangioma as potentially aggressive when any of these is present.

• Pain that is progressive rather than mechanical and intermittent, or pain or deficit worsening over weeks to months
• Any neurological signs: weakness, a sensory level, sphincter change
• Imaging showing low T1 signal, cortical expansion or bony destruction, or soft-tissue or epidural extension beyond the vertebral body into the canal
• Involvement across the whole body extending into the pedicle, lamina or posterior elements
• Symptoms that appear or worsen during pregnancy

The classic fatty lesion is unmistakable. The atypical (low-fat) haemangioma is the one that causes diagnostic difficulty, because, like a metastasis, it is T1-hypointense.

Bone scintigraphy. Scintigraphy helps when the picture is equivocal. Most haemangiomas show only normal or mildly increased uptake (and may be photopenic), whereas most metastases are markedly hot; an aggressive haemangioma can itself be active, though, so a positive scan does not exclude it. When doubt remains after CT and MRI, particularly for a T1-dark, atypical or aggressive-looking lesion in a patient with a known or suspected primary, the issue is settled by image-guided biopsy along an excisable tract in a specialist unit (see biopsy under Investigations) rather than by imaging alone.

Observation, the default. The typical incidental fatty lesion needs no treatment. Recognise it, document it and reassure the patient; routine surveillance imaging of a classic asymptomatic lesion is generally unnecessary. Observation carries no morbidity, but it depends on being confident of the diagnosis. The clinical skill is restraint: not biopsying, not irradiating and not operating on a lesion that is doing no harm.

The painful, neurologically intact lesion. When a lesion is convincingly the source of mechanical back pain and there is no neurological deficit, minimally invasive options are first-line. The choice between them is individualised and often multidisciplinary.

Vertebroplasty. Percutaneous injection of cement into the lesion relieves pain quickly, stabilises the vertebra and can devascularise the lesion. It is widely used for painful and selected aggressive lesions, including with epidural extension in some series, but is limited for cord disease alone.

Radiotherapy. External beam radiotherapy, commonly around 40 Gy in fractions, gives durable pain control and can induce re-ossification. It is effective as a first-line option for painful lesions. Other adjuncts include sclerotherapy or ethanol injection to obliterate the vascular channels.

Radiotherapy and the cord. Radiotherapy is slow in onset and is not a treatment for acute cord compression. For aggressive lesions with only a mild or slowly progressive deficit, it has been used first-line, reserving surgery for severe or progressive cord compression (Wang 2018, in the evidence below), though seven of those twenty patients went on to need an operation.

The aggressive lesion with deficit. This is the surgical group, and the principles are consistent across the literature: control the blood supply first, then decompress the cord and stabilise the spine. It is a major operation on a highly vascular lesion, and the sequence is:

1. Preoperative embolisation - transarterial embolisation of the feeding vessels to reduce intraoperative haemorrhage. Essential, and near-universal before resection of an aggressive lesion
2. Decompression - remove the epidural component compressing the cord or roots. Restoring neurological function is the primary surgical goal
3. Tumour removal, tailored in extent - ranging from intralesional resection or decompression with vertebroplasty, through gross-total or subtotal resection, to total en bloc spondylectomy for the most aggressive lesions
4. Stabilisation, if unstable - instrumented fusion where bony resection or destruction has produced instability, often guided by the SINS score
5. Adjuvant radiotherapy, if residual - postoperative radiotherapy for residual tumour after subtotal resection, to reduce recurrence

How much surgery. There is no single correct operation. Reported series show that decompression with vertebroplasty and intralesional resection can give good neurological recovery with low recurrence, while total en bloc spondylectomy gives excellent local control but carries higher morbidity. Match the aggressiveness of the operation to the aggressiveness of the lesion and the patient's fitness.

Outlook. The prognosis is excellent, and the typical incidental lesion never causes a problem. Even in the aggressive group, modern series report that neurological function improves in the great majority of patients after treatment, with low recurrence rates, when the blood supply is controlled and the cord is adequately decompressed. Malignant transformation does not occur.

There is no large randomised evidence base for vertebral haemangioma because symptomatic disease is rare; practice is therefore guided by retrospective series and the principles of benign spinal tumour surgery. Across high- and lower-resource settings the constant themes are recognition of the classic imaging signs, restraint with incidental lesions, embolisation before any major resection, and matching the intensity of treatment to the behaviour of the lesion. Resource-rich units may have ready access to en bloc spondylectomy and interventional radiology, while in other settings decompression with vertebroplasty and radiotherapy are pragmatic and effective alternatives.