Angiocentric glioma

Angiocentric gliomas are rare superficial slow-growing brain tumours typically presenting in young patients with intractable partial epilepsy 1-6. They were first introduced in the 2007 (4th edition) of the WHO brain tumour classification, and are classified as WHO grade I tumours 1

On imaging they usually present as well-delineated cortically based lesions that expand affected gyri, which are generally hypointense on T1 and hyperintense on T2 and have no contrast enhancement. 

For a general discussion of clinical presentation, epidemiology, treatment please refer to the article on low-grade astrocytomas

Angiocentric gliomas are very rare tumour with relatively few reported cases. They usually affects children and young adults 1,6. No reported gender predilection has been reported 1

Seizures are often classical presentation: >95% of patients present with intractable seizures 3.  

Angiocentric gliomas are designated as WHO grade I tumours 1-3. The exact aetiology of angiocentric gliomas remains unclear although some features are similar to ependymomas 1,6. In fact, sometimes, a distinct ependymoma component may co-exist 1

Microscopic appearance

These tumours demonstrate a monomorphic population of elongated spindle-shaped bipolar cells with a strikingly perivascular orientation, somewhat reminiscent to perivascular pseudorosettes 1,6. Although tumour cells do extend into the surrounding parenchyma, a strong for perivascular spread is evident 6. Subpial growth, along the surface of the cortex, is also a prominent feature 1,6.  

Immunophenotype

The immunophenotype shares some similarities to ependymomas 1

  • GFAP: positive
  • EMA: both surface and perinuclear cytoplasmic dot may be present

Ki-67 index is usually <5% 1

They do not demonstrate neuronal markers (e.g. synaptophysin, chromogranulin-A, NeuN) and they are IDH negative. 

Associations

Cortical dysplasia may be associated . 

  1. Angiocentric gliomas are usually supratentorial cortical or subcortical (grey-white matter junction) tumours with a tendency to spread horizontally in the subpial plane, and deeply along vessels 1. 
CT

Typically appear as an expansile non-enhancing cortical tumour.

MRI 
  • T1: hyperintense signal rim may be seen 
  • T2 / FLAIR
    • hyperintense signal
    • extension toward the ventricles along vessels
    • may have cystic appearing areas
  • T1 C+ (Gd): no enhancement

Angiocentric glioma was initially identified in 2005 in two separate case reports 2,5 and then introduced in the WHO classification of CNS tumours in 2007. It remains an entity in the current (2016) classification 1

Given their rarity, on purely imaging grounds it is difficult to distinguish these tumours from more common diffuse gliomas (both astrocytoma and oligodendroglioma). Other imaging differential considerations include:

Share article

Article Information

rID: 21730
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • ANET
  • Angiocentric gliomas
  • Angiocentric neuroepithelial tumor (ANET)
  • Monomorphous angiocentric glioma

Support Radiopaedia and see fewer ads

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.