1. Orbital lymphoma (mantle cell): irregular enhancing, T2 isointense to hypointense tissue in left orbit encasing the optic nerve sheath with associated restricted diffusion. Mild surrounding infiltrative changes/edema in the left orbital fat and muscles. Also mildly enlarged left lacrimal gland. Additional smaller similar appearing lesions in the right orbit without mass effect.
DDx: Optic nerve sheath meningioma, idiopathic orbital inflammation