Astrocytomas are intracranial tumors derived from astrocytes. They can have narrow or diffuse zones of infiltration.
WHO Grading System for Astrocytomas
- WHO Grade 1 — pilocytic astrocytoma
- WHO Grade 2 — astrocytoma
- WHO Grade 3 — anaplastic (malignant) astrocytoma
- WHO Grade 4 — glioblastoma multiforme (most common)
The prognosis is worst for Grade 4 gliomas, with an average survival time of 14-18 months. Overall, the five year survival rate is 5%.