Treatment Practices in Optic Nerve Glioma

Optic nerve glioma (OPG) is a rare tumor in children and adolescents. It comprises 1–5% of central nervous system tumors. It can be sporadic or associated with the neurofibromatosis 1 (NF1) gene. These are usually slow-growing tumors and may remain localized to the optic nerve or can have encroached upon adjoining structures like optic chiasma, opposite optic nerve, and hypothalamus. So, there may be decreased or loss of vision, proptosis, focal neurological symptoms, precocious puberty, and short stature. Due to the involvement of these critical structures, its treatment should be based on multidisciplinary consensus. The treatment modalities include surgery, RT, and chemotherapy. The aim of the treatment should be to preserve vision. However, the timing and selection of optimal treatment modalities are always a clinical dilemma. Recently, there have been promising results with newer techniques of radiotherapy and chemotherapy.

LGG-10. AN UNUSUAL PRESENTATION OF BILATERAL OPTIC NERVE GLIOMA IN CROUZON SYNDROME

Optic pathway gliomas (OPGs) are low grade gliomas intrinsic to the visual pathway, frequently associated with Neurofibromatosis Type 1 (NF-1). Bilateral OPGs without chiasmatic involvement are almost pathognomonic for NF-1. We report an unusual case of bilateral optic nerve glioma without chiasmatic involvement in a 17-month old male patient with craniosynostosis and Crouzon Syndrome, an autosomal dominant disorder caused by activating FGFR2 mutations associated with craniosynostosis and optic atrophy. The patient’s c.1032 G>A pathogenic variant in FGFR2 is a variant known to affect splicing and results in a protein that lacks part of an important domain involved in ligand binding. Although FGFR1 mutations have been implicated in low-grade glioma through MAPK activation, FGFR2 mutations have not yet been described in OPGs, although they have been described in epileptogenic low-grade gliomas and mixed neuronal-glial tumors. Our patient presented with worsening vision in the setting of known Crouzon Syndrome. An eye examination revealed bilateral primary optic atrophy. Brain and orbital MRIs demonstrated fusiform dilation and STIR hyperintensity of the intraorbital segments of the optic nerves bilaterally with normal pre-chiasmatic optic segments. There were no other radiographic or physical stigmata suggestive of NF-1. Next generation sequencing and copy number analysis from peripheral blood were negative for variants in NF1. RNA based studies for NF1 aberrations are pending. Although follow up MRI scans demonstrated stable size of his OPGs, the risk of further visual deficit was considered significant due to his pre-existing optic atrophy and poor baseline visual acuity. Therefore, he was started on vincristine and carboplatin chemotherapy according to A9952, and induction therapy has been well tolerated. To our knowledge, this is the first patient with Crouzon Syndrome who has developed bilateral optic pathway gliomas. Orbital MRIs should be considered for these patients with worsening visual acuity not explained by other causes.

Optic neuropathy secondary to probable optic nerve glioma: case report

Introduction: Optic neuropathies are a group of pathologies that course with potentially irreversible visual dysfunction. Among compressive causes, optic nerve glioma (GNO) is one of the main ones. Case report: A 12-year-old black school-age female patient seen in February 2020, reported progressive low visual acuity on the right eye (RE) for 6 years. Ectoscopy revealed café au lait spots all over body and hyperchromic nodular lesion in left axilla. Ophthalmologic examination showed acuity of 20/400 in RE and 20/20 in the left eye (LE), relative afferent pupillary defect in RE. At biomicroscopy, irian Lisch nodules. Magnetic resonance imaging (MRI) showed fusiform thickening of intraorbital portion of right optic nerve (ON) with mild enhancement upon gadolinium infusion. Optic neuropathy was secondary to probable GNO. Ophthalmology and neurology management was expectant. Upon return, patient reported intermittent headache and functional and aesthetic discomfort due to axillary lesion, and presented a new MRI with findings similar to the first. Simple retinography showed global pallor in right ON and temporal pallor of left ON. Conclusion: The case presented, in which delay in access to specialized care resulted in blindness, highlights the importance of ophthalmologic screening in NF1. Manifestations resulting from the syndrome, with biopsychosocial repercussions, emphasize importance of multidisciplinary care.