Visual Symptomatology Outpaces Anatomical Optic Nerve Changes in Optic Nerve Glioma: Clues to Earlier Detection and Diagnosis

Objective: Glioblastoma multiforme of the optic nerve is rare, often has a rapidly progressive course with visual declines, and spreads throughout the cerebrum. Early diagnosis can be difficult and relies on accurate ophthalmologic examination and imaging. We sought to identify factors of ophthalmologic workup that may be helpful in early identification of these aggressive lesions.

Methods: Retrospective review of medical records from the University of Virginia Hospital from 1998-2012. All patients with GBM involving the optic nerve or chiasm were included. Patient and tumor characteristics, as well as preoperative ophthalmologic workup, treatment course, and outcomes, were recorded.

Case Series: Three cases were included in the series. In the first case, a 60-year-old man presented with decreased visual acuity in the right eye. Examination revealed a right central scotoma with superior and inferior arcuate changes and left temporal desaturation, suggesting a junctional syndrome of Traquair. There was a right APD, but OCT demonstrated normal macula and optic nerve thickness. The visual symptoms were out of proportion to the OCT changes, suggesting a rapidly progressive pathological process. Imaging revealed an enhancing lesion on the right side of the optic chiasm extending into the right optic nerve and right optic tract. The patient underwent biopsy, which revealed GBM. The patient experienced progressive left-sided vision loss associated with progression of the lesion on MR imaging.

The second case describes a 79-year-old man who presented with a visual field defect and was found to have a dense right homonymous hemianopia and a subtle right APD, without evidence of nerve fiber layer dropout on OCT. He did have severe inferotemporal macular thinning, potentially related to a branch macular artery occlusion. MR imaging revealed a 1.7 x 1.5-cm enhancing left optic chiasm, left optic tract, and temporal lobe lesion involving the cerebral peduncle and pons. The patient was taken for stereotactic biopsy, followed by temozolomide therapy and fractionated radiotherapy.

The third case describes a 70-year-old man who presented with a 2-month history of diplopia on rightward gaze and ptosis. He had a history of left thalamic ischemic stroke 9 years prior, ALS, and glaucoma. Examination revealed pupil-sparing oculomotor nerve palsy with 20/20 vision and an incomplete left homonymous hemianopia without APD, but a moderate right-sided optic neuropathy was seen that was thought to be due to glaucoma. There were also dramatically slowed saccades thought to be related either to ALS or the hypothalamic component of the lesion. Stereotactic biopsy revealed a high-grade glioma, and the patient was treated with radiotherapy and temozolomide.

Conclusions: Optic nerve GBM appears to present with compressive symptoms out of proportion with anatomical changes to the optic nerve, likely due to the rapid progression of nerve compression and symptom onset. The recognition of this disparity on initial ophthalmologic evaluation may promote early imaging and treatment of these aggressive lesions.