Astrocytoma

Astrocytomas are primary central nervous system (CNS) tumours that typically located in white matter. They arise from (no surprises here) astrocytes and are the most common glial tumour.

They are divided into:

• diffuse astrocytoma or low grade astrocytoma: WHO grade II  (10-15% of astrocytomas)
  • fibrillary astrocytomas
  • protoplasmic astrocytoma
  • gemistocytic astrocytoma
• anaplastic astrocytoma: WHO grade III (25% of astrocytomas)
• glioblastoma: WHO grade IV (50-60% of astrocytomas)

A number of other astrocytic tumours also exist, although they are usually considered separately. These include:

• pilocytic astrocytoma: 9421/11 - WHO grade I
• pilomyxoid astrocytoma: 9425/3* - WHO grade II
• subependymal giant cell astrocytoma: 9384/1 - WHO grade I
• pleomorphic xanthoastrocytoma: 9424/3 - WHO grade II

Additionally some tumours also contains astrocytic components, and it is often this component that dictated biological behaviour. Examples include:

• ganglioglioma
• oligoastrocytoma