Which one of the following is the least likely cause of this patient's symptoms of retrobulbar swelling and diplopia?

Answer A. DermatomyositisCerebral venous thrombosis can present with retrobulbar pain and vision changes. Risks for cerebral venous thrombosis include infections (sinus and ear), hypercoagulopathy, cancer, trauma, and the use of certain drugs. In this case, sinus infection can spread with direct extension or travel from mucosal veins to the venous sinuses.