Subarachnoid and intraventricular dissemination of silicone oil: an under-recognised radiological diagnosis

A woman aged in her 50s presented with sudden onset of vertigo, headaches and epistaxis, initially attributed to her background of chronic systemic hypertension. Ophthalmological history was significant for bilateral proliferative diabetic retinopathy and retinal detachment managed with vitrectomy, endolaser and intraocular silicone oil 5 years prior to the current presentation. Review of the initial non-contrast CT by our neuroradiology department identified right subretinal silicone oil, tracking along the subarachnoid space of the right optic sheath, right suprasellar cistern and non-dependent lateral ventricles. Initially interpreted as acute haemorrhage at an external facility, the patient underwent repeat imaging over a period of 6 months that failed to demonstrate expected temporal resolution of blood products. A subsequent unifying diagnosis of disseminated subarachnoid and intraventricular silicone oil was established. The following case highlights the relevant clinical history when requesting imaging and pertinent radiological findings when reporting patients postretinal detachment surgery.