Optic Neuropathy Revealing Severe Superficial Siderosis in the Setting of Long-standing Low-grade Intracranial Neoplasm

Hemptinne, Coralie [UCL] Coche, Adrienne [UCL] Duprez, Thierry [UCL] Demaerel, Philippe Raftopoulos, Christian [UCL] Boschi, Antonella [UCL]

Two cases of optic neuropathy due to superficial siderosis (SS) are reported in two patients, aged 29 and 38 years, operated for intracranial neoplasms, the first one with a desmoplasic infantile ganglioglioma excised in 1991, and the other one with a pilocytic astrocytoma, operated on in 1997, 1998 and 2016. Both patients presented with progressive loss of visual acuity, as a result of bilateral optic nerve atrophy, as well as unsteadiness, ataxic gait and hearing loss. Magnetic resonance imaging (MRI) of the brain and spine, including gradient echo (GRE) T2-weighted acquisitions, revealed thin optic nerves and strong hypointensity with susceptibility artefacts corresponding to haemosiderin deposits within the meningeal layers of the spine, the infra- and supratentorial spaces of the brain and the peri-optic sheaths in both patients. The cerebrospinal fluid (CSF) was macroscopically haemorrhagic in one patient, who underwent a dynamic myelography, which failed to reveal any trans-dural CSF leakage. Neuro-ophthalmological symptoms due to SS, such as visual acuity loss, have been scarcely reported. MRI using GRE T2-weighted sequences highlighting the presence of haemosiderin deposits plays a key role in the diagnosis of this condition. Treatment should aim at preventing haemosiderin deposition by treating the cause of the subarachnoid bleeding.