The cause is unknown.
Aggressive treatment is required to affect a cure.
Grade 1 and 2 tumors are considered low grade and Grade 3 and 4 are high grade. A Grade 1 tumor has a lobular architecture, may or may not have rosettes, and has no mitotic activity, nuclear pleomorphism or necrosis. A Grade 4 tumor may or may not have a lobular architecture, has no rosettes, but necrosis is common and there is marked mitotic activity and nuclear pleomorphism. Anosmia, proptosis, and visual disturbances may occur. Other patients present with headaches or facial pain.