Optic Nerve Glioma Masquerading as Optic Neuritis in a Young Woman

A 28-year-old woman experienced slowly progressive vision loss of her right eye with transient right eye pain.

Poster 186 Optic Nerve Glioma Masquerading as Optic Neuritis in a Young Woman Rachel Patel1, Kathleen Digre1, Cheryl Palmer2, Bhupendra Patel1, Blair Winegar3, Alison Crum1, Bradley Katz1, Meagan Seay1, Judith Warner1 Moran Eye Center, University of Utah, Salt Lake City, Utah, USA, 2Department of Pathology, University of Utah, Salt Lake City, Utah, USA, 3Department of Radiology, University of Utah, Salt Lake City, Utah, USA 1 Introduction: A 28-year-old woman experienced slowly progressive vision loss of her right eye with transient right eye pain. Description of Case(s): On initial exam, six months after symptoms began, her visual acuity was counts fingers at 2 feet OD and 20/20 OS, with grade 4 optic disc edema of the right eye. MRI of the brain and orbits demonstrated enlargement and enhancement of the right intraorbital optic nerve with sparing of the most anterior component. The rest of the brain and spinal cord MR was normal. Laboratory workup was normal, including anti-AQP4 and anti-MOG. Lumbar puncture showed a normal opening pressure with normal CSF analysis. She received two courses of IV methylprednisolone and extended oral prednisone taper without improvement. Repeat MRI demonstrated persistent enhancement of the right optic nerve extending more posteriorly along the intraorbital segment. A workup for systemic malignancy was non-contributory. Visual acuity declined to no light perception with unchanged optic disc edema OD. She underwent optic nerve biopsy via superomedial lid crease approach, demonstrating a hypercellular nerve without evidence of malignancy. Most myelin was retained. A repeat biopsy was performed via a lateral orbitotomy to access more posterior optic nerve; histopathology revealed atypical glial proliferation consistent with a low-grade optic nerve glioma. She underwent en bloc resection of the right optic nerve by frontotemporal craniotomy and has not required adjuvant therapy to date. Conclusions, including unique features of the case(s): While clinical presentation was most suspicious for inflammatory optic neuritis, the absence of improvement despite multiple rounds of steroids raised concern for malignancy. Initial optic nerve biopsy suggested chronic neuritis but likely sampled too anterior a portion of nerve; repeat biopsy via lateral orbitotomy allowed more posterior sampling and confirmed low-grade optic glioma. Optic nerve gliomas must be considered on the differential for optic nerve enhancement, particularly when the clinical course is atypical for optic neuritis. References: 1. Thorne AH, Zanca C, Furnaru F. Epidermal growth factor receptor targeting and challenges in glioblastoma. Neuro Oncol. 18, 914-8, 2016. 2. Karsy M, Guan J, Cohen AL, Jensen RL, Colman H. New molecular considerations for glioma: IDH, ATRX, BRAF, TERT, H3K27M. Curr Neurol Neurosci Rep. 17, 9, 2017. Keywords: tumors, optic neuritis Financial Disclosures: The authors had no disclosures. Grant Support: Supported in part by an Unrestricted Grant from Research to Prevent Blindness, New York, NY, to the Department of Ophthalmology & Visual Sciences, University of Utah. Contact Information: Rachel Patel, MD, [e-mail] 186 | North American Neuro-Ophthalmology Society