A 21-year-old, otherwise well man presented with a 3-month history of bilateral deteriorating vision. His visual acuity was 6/60 on the left and 6/12 on the right. Fundus examination revealed bilateral papilloedema, with optic discs grossly swollen and bulging forward (Figure: A, left eye; B, right eye). There were bilateral haemorrhages of the retinal nerve fibre layer surrounding the disc, and macular folds (Figure, arrows). An urgent computed tomography scan revealed a 5.8 cm × 5.3 cm mass in the inferior right frontal lobe, with cystic and necrotic components. The patient was referred for urgent surgical debulking. Histopathological examination of the mass confirmed that it was a high-grade anaplastic astrocytoma.