CNS capillary telangiectasia

CNS capillary telangiectasiae(s) are small, asymptomatic low flow vascular lesions of the brain. 

Epidemiology

As these lesions are asymptomatic, diagnosis usually matches the age of first imaging with MRI, and as such are most frequently found in middle aged and elderly adults. Their incidence varies according to the series. They can account for up to ~20% of all intracerebral vascular malformations on autopsy studies ² and are considered the second most common vascular anomaly after venous angiomas (developmental venous anomaly) on imaging ⁵.

Clinical presentation

The vast majority of capillary telangiectasias are completely asymptomatic and discovered incidentally on MRI, when the brain is imaged for other reasons. 

Occasionally there may be associated intracerebral haemorrhage, although a direct causative relationship has not been established beyond a doubt. 

Pathology

They are comprised of dilated capillaries and are interspersed with normal brain parenchyma with a thin endothelial lining but no vascular smooth muscle of elastic fiber lining. This is in contrast to cavernous malformations (cavernous haemangiomas) which have no normal brain within their confines. 

Location

Most occur in the pons, cerebellum and spinal cord.

Associations

• Osler-Weber-Rendu syndrome 

Radiographic features

Capillary telangiectasias are most are located within the brainstem and pontine regions, and are more commonly multiple. They have only become widely recognised in the radiology community following introduction of MRI, as they are invisible both on CT and DSA ^2-5. 

MRI Brain

Seen as subtle lesions with no mass effect

• T1: typically iso to low signal compared with brain parenchyma
• gradiant echo (GE): typically low signal
• T2: slightly increased signal intesnsity
• T2*: low signal intensity (thought to be due to deoxyhaemoglobin ²)
• T1 C+ (GAD): may demonstrate ill-defined focal enhancement

Treatment and prognosis

As these lesions are almost always asymptomatic, have interspersed normal brain tissue and are most frequently located in the pons, makes treatment impractical and unwarranted. 

No followup is thus required if the imaging appearances are characteristic. 

Differential diagnoses

In the majority of cases, no differential needs to be entertained. When appearances are atypical then depending on the actual appearance, one could consider:

• enhancing mass (usually mass effect present)
  • glioma
  • metastasis
• resolving infarct
• demyelination
• cerebritis
• vascular malformation
  • cavernous malformation
  • areteriovenousarteriovenous malfomation (AVM)
  • developmental venous anomaly (DVA)