Neuroophthalmological management of optic pathway gliomas

Abstract

✓ The growth rate of optic pathway gliomas (OPGs) is unpredictable and quite variable, especially in children with neurofibromatosis Type 1 (NF1). Close neuroophthalmalogical clinical follow-up with serial imaging (magnetic resonance imaging of the brain with and without contrast enhancement) is the recommended initial step in management to establish the growth rate of the lesion in an individual patient. Typically, only symptomatic and/or radiographically growing tumors require treatment, and observation is the accepted first-line option. Although both chemotherapy and radiotherapy can stabilize growth or even decrease the size of tumors, chemotherapy, especially in younger patients, has fewer side effects than radiation therapy (such as secondary tumors, radiation necrosis, and Moyomoya disease) and is generally considered the first-line treatment for progressive lesions in younger patients. The tumor location defines prognosis in OPGs; optic nerve gliomas (ONG) have the lowest rate of complications and death, and optic chiasm and retrochiasmal gliomas the highest. Although the major complication of an OPG is visual loss, hypothalamic involvement can lead to death. Resection is an option for ONGs but is generally reserved for tumors confined to the optic nerve with poor or no vision, or for patients with severe, cosmetically unappealing proptosis, producing severe pain or exposure keratopathy in a blind eye. Resection is generally not an option for intrinsic chiasmal or retrochiasmal OPGs. Extrinsic (exophytic) components can be debulked surgically, and surgery can be performed for hydrocephalus (ventriculoperitoneal shunt placement). The approach to a patient with OPG must be individualized based on tumor location, radiographic or clinical progression, the presence of NF1, and a risk–benefit comparison for treatment.