Aggressive vertebral hemangioma

Aggressive vertebral hemangiomata are a rare form of vertebral hemangiomata where significant vertebral expansion, extra-osseous component with epidural extension, disturbance of blood flow, and occasionally compression fractures can be present causing spinal cord and/or nerve root compression ^1,2. 

Epidemiology

It can occur at any age, with peak prevalence in young adults. They represent approximately 1% of spinal hemangiomas and are usually symptomatic ¹. 75% of these lesions occur in the thoracic spine between T3 and T9 vertebral segments ³.

Clinical presentation

Unlike typical vertebral hemangiomas which are almost always asymptomatic, aggressive type virtually always present with neurological manifestations due to the mass effect of the epidural component upon the spinal cord, nerve roots or both, leading to compressive myelopathy and/or radiculopathy ².

Pathology

They are composed of blood vessels with slow flowing, dilated venous channels surrounded by fat, infiltrating the medullary cavity ⁴.

Radiographic features

CT

They appear as hypodense expansile vertebral masses, with cortical defects and soft tissue extension and spinal cord/nerve root compression. The classic “polka dot” and “corduroy” signs of the vertebral body due to thickened vertebral trabeculae are also helpful ¹. They generally occupy the entire vertebral body, extend into the neural arch, expand the osseous margins, and contain a soft tissue component ¹.

MRI

Thickened trabeculae appear as low signal areas in both T1 and T2 images. The extraosseous component typically follows usual hemangioma features in all pulse sequences with high T1 and T2 signals as well as uniform post-contrast enhancement. MRI is excellent for the assessment of cord or nerve root compression ¹.

Chemical shift imaging can be helpful to look for signal dropout to indicate intralesional fat.

Treatment and prognosis

Accurate preoperative diagnosis is essential because they are highly vascular with a high tendency of intraoperative bleeding. Surgery is required in cases of rapid or progressive neurological symptoms like compressive myelopathy or radiculopathy. Endovascular embolization prior to surgery to minimize intraoperative blood loss is sometimes performed. Radiotherapy can be used in patients with slowly progressive neurological deficits. Other emerging options in cases of aggressive hemangiomas include radiofrequency ablation with a hemostatic agent (e.g. FLOSEAL, Baxter, USA), and bone autograft placement ⁶. Minimally invasive procedures may be successful in smaller lesions ⁵.

Differential diagnosis

• plasmacytoma: has characteristic mini-brain appearance

• metastases: usually have decreased signal intensity on T1 and increased signal intensity on T2

• lymphoma: epidural component appears hypointense on T1 and less hyperintense on T2

• chordoma: can look very similar on T2 and post-contrast imaging but usually does not have high T1 signal, frequent peripheral calcifications can mimic thickened trabeculae of vertebral hemangioma