Radiation-induced central demyelination, report of a rare subacute complication and review of the literature

A 26-year-old woman with a right frontal diffuse astrocytoma, isocitrate dehydrogenase-mutant, WHO Grade II was treated with resection and radiotherapy (54 Gy in 30 fractions by volumetric modulated arc therapy). Ten weeks after radiation, she developed left leg weakness, and a brain magnetic resonance image demonstrated multifocal acute demyelinating brain lesions within regions that received 10-30 Gy. She improved with high dose steroids and subsequently resumed temozolomide. She had no prior history of a demyelinating disorder. The mechanisms of neurotoxicity from radiation include vascular injury, demyelination, and oxidative damage to neural stem cells and oligodendrocytes; though the pathophysiology is not fully understood. Subacute demyelination in the absence of known demyelinating disease is rare with only four cases previously described. This rare complication can be successfully managed with steroids when symptomatic. It is important to consider demyelination if new distant enhancing lesions arise following radiation of a primary brain tumor when findings are atypical for recurrence.