Optic pathway gliomas in patients with neurofibromatosis type 1: follow-up of 44 patients

Abstract

Background: Children born with neurofibromatosis type 1 (NF1) have an increased risk of developing optic pathway gliomas (OPGs) during childhood. The aim of this study is to evaluate the clinical course of NF1 patients with OPGs at our institution with respect to visual and endocrinologic morbidity.

Methods: Retrospective case series of patients with OPGs and NF1 seen at the Montreal Children's Hospital, where screening imaging is performed on all NF1 patients. Details on patient demographics, tumor location, and progression of disease were recorded.

Results: Of 331 NF1 patient charts reviewed, 44 had confirmed OPG (13%). Average follow-up was 7 years. Mean age at presentation was 6 years, with 16 patients (36%) presenting past age 6. A total of 8 patients were symptomatic secondary to the OPG (defined as decreased vision or precocious puberty), with 5 of the 8 patients receiving treatment. These 8 patients all demonstrated chiasmal and/or retrochiasmal tumor in addition to nerve involvement. Final visual acuity was 20/40 or better in both eyes in 34 patients (77%); central, steady, and maintained in 3 preverbal children; and decreased vision secondary to OPG in 4 children (9%).

Conclusions: OPGs can present and progress beyond the preschool years, and children should be screened with clinical ophthalmological examinations accordingly. The location of OPG as demonstrated on magnetic resonance imaging (MRI) cannot be used as a prognostic indicator because visual outcomes were similar between optic nerve/chiasmal and retrochiasmal tumors.