Brain tumour. Computed tomography (CT) scan of an axial section of the brain of a 44-year-old female patient with a sphenoid wing meningioma in the left hemisphere (centre, white). Sphenoid wing meningiomas are slow-growing benign (non-cancerous) brain tumours found near the sphenoid bone (bony ridge behind the eyes). Meningiomas (meningeal tumours) form on the meninges, the membranous layers surrounding the brain and spinal chord. Sphenoid wing meningiomas may cause vision problems, or facial numbness. These tumours can often surround major blood vessels (eg. carotid arteries) and cranial nerves, making them difficult to completely remove. This is a CT scan under intravenous iodine injection.