[Optic nerve glioma in children].

Optic pathway gliomas are rare tumors accounting for 3-5% of brain tumors in children; 90% are observed in children. They account for 4% of orbital tumors in children. Association with NF 1 is classical and the incidence of NF 1 in patients with optic pathway gliomas is estimated at 30-58%. Usually these tumors are pilocytic astrocytomas and their regression, particularly in patients with NF 1, has been described. Exophthalmos and loss of visual acuity or blindness are the usualpresentation in progressive disease. CT and above all MRI study of the orbit and the brain are necessary to make a complete evaluation of the disease. Gross total removal of the tumor provides 100% cure, but surgery can be proposed only for growing tumor with severe exophthalmos and no useful field of view or blindness. Chemotherapy must be proposed as first-line treatment for growing tumor with moderate exophthalmos and useful vision when the tumor is strictly confined in the orbit. The place of radiotherapy for pure intraorbital gliomas has not been defined and proton beam therapy has to be evaluated.