About
Brain Tumors
A
tumor is a mass or growth of abnormal cells. Brain
tumors typically are categorized as primary or
secondary. Primary brain tumors originate in the
brain and can be benign (slow growing) or
malignant (fast growing). Secondary brain tumors (metastatic
brain tumors), which are malignant, are more
common. These tumors result from cancer that
started elsewhere in the body and spread
(metastasized) to the brain.
Brain
tumors may be classified as gliomas or non-gliomas.
The most common gliomas are astrocytomas,
oligodendrogliomas (mixtures of oligodendroglioma
and astrocytoma elements), and ependymomas. Most
gliomas infiltrate critical brain tissue in such a
way that surgical removal is impossible.
Non-gliomas
consist of typically benign tumors such as
meningiomas and pituitary adenomas, as well as
malignant tumors such as primitive neuroectodermal
tumors (medulloblastomas), primary central nervous
system (CNS) lymphomas, and CNS germ cell tumors,
which occur rarely.
