Ptosis due to Extraocular Muscle Swelling

60-year old gentleman presented with 5-day history of left sided ptosis and proptosis. He had conjunctival congestion. He was a diabetic, however, he had no history of thyroid disease. MRI brain showed swelling of left superior rectus, levator palpebrae superioris and lateral rectus muscles on the left side. Differential diagnosis include: Thyroid eye disease, idiopathic