What is the difference between a grade IV astrocytoma, a malignant glioma and a glioblastoma multiforme (GBM)?
A. Brain tumor names can be quite confusing. Tumors that arise from the support cells in the brain are called gliomas. They can be low grade malignancies (low grade gliomas) or more aggressive high grade gliomas (malignant gliomas). Ependymomas, medulloblastomas, oligodendrogliomas and astrocytomas are all gliomas arising from different types of support cells, or glia. Like all gliomas, astrocytomas can be low grade malignancies (low grade astrocytomas), mid-grade malignancies (anaplastic astrocytomas) or high grade malignancies (glioblastoma multiforme or GBM). Another way of describing this increasing grade of aggressiveness is with a number grading system from I-IV, with grade four being the most malignant. Depending on the context, grade IV astrocytoma, malignant glioma and GBM can all be used to describe the same tumor.
