Optic gliomas in children with neurofibromatosis type 1

Abstract

Over a 24-year period, optic gliomas were found in 29 children, 16 of whom had neurofibromatosis type 1 (NF-1). These 16 children comprised 21% of all children referred for management of NF-1 and its complications. The finding of optic glioma led to the diagnosis of NF-1 in 4 children. The mean age at diagnosis of optic glioma in NF-1 children was 6.4 years, and the average estimated duration of visual symptoms prior to diagnosis was 2.1 years. Most optic gliomas in NF-1 children were ascertained because of a visual complaint (69%), and an even greater number of children (88%) had an abnormal ophthalmological examination. The optic chiasm was involved in 75% of the patients. All of the seven children with optic glioma examined by visual evoked potential had an abnormal response ipsilateral to the tumour. The majority of the children received radiation therapy. After a mean follow up period of 5.8 years no deaths had occurred due to optic glioma, but in 35% of the children vision was worse. We conclude that optic glioma is a common, serious complication in NF-1 children. Routine care of such patients should include regular noninvasive investigations aimed at detecting lesions of the optic pathway.

Screening children with NF1 for optic pathway glioma – No

“…Clinical examination (including visual acuity) yields positive findings in only 20-54% patients with proven OPG. 4,7 Fundus examination is possible in all children, although there are no data to suggest that optic atrophy would constitute an early diagnosis. The presence of optic atrophy would suggest that visual acuity would be affected.…”

Functional outcome measures for NF1-associated optic pathway glioma clinical trials

“…Visual evoked potentials (VEPs) are an electrophysiologic test believed to provide a functional measure of visual pathway integrity. Although VEP testing may detect OPG with some sensitivity, [42][43][44][45][46] some patients with NF1 have abnormal VEP testing despite no evidence of glioma. 47 Of greater concern is the poor diagnostic sensitivity of VEP for VA loss 48 and the poor correlation of VEP changes over time with VA changes and response to treatment.…”

Can Screening for Optic Nerve Gliomas in Patients With Neurofibromatosis Type I Be Performed With Visual-Evoked Potential Testing?

“…1,3 Both the incidence and morbidity related to these tumors is high in patients with NF1; yet, the natural history and most appropriate screening examination is controversial. 4 Optic nerve and pathway gliomas (ONGs) usually are diagnosed early in a patient's life, with a median age of onset of 4.5 years, and rarely become symptomatic after age 10. 1,4 Treatment is currently only recommended when tumors are symptomatic and show evidence of progression.…”

“…4 Optic nerve and pathway gliomas (ONGs) usually are diagnosed early in a patient's life, with a median age of onset of 4.5 years, and rarely become symptomatic after age 10. 1,4 Treatment is currently only recommended when tumors are symptomatic and show evidence of progression. Currently, annual ophthalmic examinations are the most cost-effective screening for gliomas; however, eye examinations often can be unreliable and inaccurate in children.…”