Glioma is a generalized term for any tumor that develops from the glia, the supportive structure that help keep the neurons of the brain in place. There are three types of glial cells: astrocytes (including gliobastomas), oligodendrocytes, and ependyomas. Names that refer to such tumors such as brain cell glioma are derived from the location of the tumor itself, not the type of tissue cell that gave rise to them. A specific diagnosis is only possible if a biopsy of the tumor is obtained.
Metastatic brain tumors are secondary tumors formed from cancer cells that migrate to the brain from a primary cancer found elsewhere in the body. Cancers that frequently do this are lung cancer, breast cancer, melanoma (a form of skin cancer), kidney cancer and colon cancer.