Presumed Malignant Optic Glioma of Adulthood: Prolonged Survival with Temozolomide and Radiotherapy

• Published in: Canadian journal of neurological sciences 2024-11, Vol.51 (6), p.888-890
• Main Authors: Tao, Brendan, Handzic, Armin, Margolin, Edward
• Format: Article
• Language: English
• Subjects: Biopsy; Glioma; Letter to the Editor: New Observation; Life expectancy; Medical imaging; Medical prognosis; Metastasis; Neuroimaging; Optic nerve; Patients; Radiation therapy; Remission (Medicine); Steroids
• ISSN: 0317-1671; 2057-0155
• DOI: 10.1017/cjn.2023.312

With only over 70 reported cases, MOGA is a rare diagnosis that mimics demyelinating optic neuritis and NMO/MOG-related optic neuritis and chiasmitis.1,2 It should be suspected in all patients with presumed optic neuritis who demonstrate no visual improvement after treatment with corticosteroids and show further optic nerve and/or chiasm enlargement on follow-up neuroimaging with otherwise negative work-up for inflammatory and infiltrative causes of optic neuropathy. Patients present with acute vision loss, that over 5-6 weeks progresses to bilateral complete vision loss in 63%.2 Neuroimaging typically demonstrates fusiform enlargement and enhancement of the intracranial optic nerve and chiasm.2 In 50% of cases, retrograde tumor progression extends to the hypothalamus, basal ganglia, and temporal lobe.2 Rarely, MOGA may lead to distal spinal metastasis.3 Our case demonstrated distal MOGA spread along neuro-axis without radiological evidence of direct extension: an intramedullary lesion extending down to thoracic cord was presumed to represent distal metastases of the optic pathway lesion with the spinal seeding likely occurring via CSF spread.4 This is similar to other malignant brain gliomas which typically infiltrate surrounding brain tissues and spread along white matter tracts.3 Patients with MOGA have a median life expectancy of less than one year with statistically significant improvement in survival in those who receive combination chemo- and radiotherapy over radiotherapy alone.5 Adjunct therapy with lomustine after disease recurrence is another option to extend survival.2 There are only a few rare reports in the literature of patients with the long survival (4.5–7 years).1 Compared to the median life expectancy of MOGA, our patient had extended survival on a regimen of temozolomide and radiotherapy, surviving two years after presumptive diagnosis before expiry. [...]while there is a dearth of molecularly characterized optic gliomas in the literature, molecular variants may have unique mutations that confer variable response to therapy and represent an opportunity for optimized molecular-targeted treatment.6 Such investigation was precluded in our patient, though their initial symptomatic presentation was markedly controlled with sustained remission for two years on their treatment regimen.