The above described features are suggestive of left optic nerve meningioma. Glioma and meningioma are the most common orbital masses. The cell of origin of optic nerve sheath meningioma is the optic nerve arachnoid sheath.

Classically, meningiomas have a “tram-track” configuration on axial images as the enhancing tumor lies on both sides of the optic nerve while the optic nerve itself does not enhance. While on coronal images, this configuration appears similar to donuts or dot sign. 

The main differential diagnosis is gliomas. It causes fusiform expansion of the optic nerve and the optic nerve could not be separated from the lesion.