The optical glioma is a primary brain tumor, which originates from cells of the glia of the central nervous system (astrocytes, oligodendrocytes, ependymal cells and microglia cells) located near one of the two optic nerves.
The optic nerves - constituting the 2nd pair of cranial nerves - transmit the visual information, coming from the ganglion cells of the retina (located on the bottom of the eyeball), to the visual cortex placed on the occipital lobe (brain region responsible for processing stimuli electric in visual images).
The optical glioma - also called for obvious reasons glioma of the optic nerve - usually derives from a genetic alteration of an astrocyte. Brain tumors with astrocytic origin are called astrocytomas, so most of the optic nerve gliomas are astrocytomas.
ASTROCYTOMES OF GRADE I AND GRADE II
Like astrocytomas, optical gliomas may have the characteristics of a grade I brain tumor (pilocytic astrocytoma) or grade II (diffuse astrocytoma).In both cases, their growth power is low, so they are not very infiltrative.
What distinguishes them is the way in which they occur: an optical glioma of the pilocytic astrocytoma type is a separate tumor mass ; an optic glioma of the diffuse astrocytoma type is a tumor dispersed in the remaining healthy brain mass.
ASSOCIATED DISEASES AND EPIDEMIOLOGY
Optical glioma is a more common brain tumor in children, especially those under 10 years.In adults it is quite rare.
20-30% of patients with an optic glioma also suffer from type 1 neurofibromatosis . Type 1 neurofibromatosis is a genetic, almost always hereditary disease that causes the onset of numerous neoplasms in the nervous system.Cancers are usually benign, but can turn into malignant ones .
