Glioma

A glioma is a brain tumor that may or may not be benign and malignant central nervous system neoplasms derived from the non-neuron glial cells (e.g., astrocytes, oligodendrocytes, and ependymocytes). In the central nervous system, "benign" and "malignant" do not have the same connotation as elsewhere in the body. A malignant CNS tumor is highly invasive within the CNS but rarely crosses the blood-brain barrier for classic metastasis into other organ systems.

Astrocytes may give rise to astrocytomas  or glioblastomas; they are less different diseases and more grading of histopathological diagnosis and aggressive behavior of the growth. Oligodendrocytes give rise to oligodendrogliomas and ependymocytes may undergo transformation to become ependyomas, choroid plexus neoplasms  or colloid cysts of the third ventricle.