Primary intraosseous haemangioma

A primary intraosseous haemangioma is a type of haemangioma which is most frequently seen in the vertebrae or skull, and come in four histological varieties ^1-2:

Epidemiology 

Intraosseous haemangiomas are common, with vertebral lesions seen in 10 -15% of the adult population. They are more commonly encountered in men (2 : 1 M : F ratio) and typically seen in the 4^th - 5^th decade of life. 

Clinical presentation

These tumors are slow growing and are generally asymptomatic unless they cause mass effect on sensitive structures. Occasionally they may present as a swelling or a palpable mass, especially in the skull. When large and strategically located they may present as a pathological fracture. 

If they are high flow lesions then shunt related symptoms may also be present. 

Pathology

Primary intraosseous haemangiomas are slow growing vascular neoplasms, usually located in the medullary cavity. They are classified as benign, but rarely may be locally aggressive.

Histological sub types

Intraosseous haemangiomas come in four histologic types: 

1. intraosseous cavernous haemangioma
2. intraosseous capillary haemangioma
3. intraosseous arteriovenous haemangioma (may represent congenital arteriovenous malformations) ²
4. intraosseous venous haemangioma

Histologically demonstrates hamartomatous vascular tissue within endothelium, but may also contain fat, smooth muscle, fibrous tissue, and thrombus.

It is important to note that it is difficult to distinguish between the various types (except for those with a large arterial component).  

Location specific sub types

• vertebral haemangioma
• sacral haemangioma
• skull vault haemangioma
• intracortical haemangioma

Radiographic features

Plain film

Plain radiographs are usually first line and may be sufficient in vertbera or calvarial lesions. Findings include:

• prominent trabecular pattern
• sclerotic vertebra with vertical trabeculae : Corduroy sign
• lytic calvarial lesions with spoke-wheel appearance
• irregular and lytic in long bones, with a honeycomb appearance

CT

Usually as an incidental finding, especially in the vertebrae. 

Better visualization of thickened vertical trabeculation (polka-dot appearance)

MRI

Signal intensity is somewhat variable, depending largely on the amount of fat content. 

• T1
  • high is more common (fat rich)
  • intermediate to low signal intensity is seen in fat poor haemangiomas
• T2 : high
• T1 C+ Gd : enhancement is often present

MRI is the ideal modality to demonstrates many mass-effect complications, such as neural impingement and extraosseous extension.

Nuclear medicine bone scan

Usually normal but may show increased or decreased uptake

Treatment and prognosis

Treatment is reserved for symptomatic lesions, and a number of modalities exists:

• radiation therapy
• embolisation to reduce intraoperative blood loss
• surgical resection, especially if complicated by spinal cord compression
• vertebroplasty
• intralesional ethanol injection