case report of bilateral cavernous sinus syndrome due to primary non-hodgkin lymphoma of the central nervous system in a patient infected by the human immunodeficiency virus. a 51-year-old male patient infected by the human immunodeficiency virus but without antiretroviral treatment developed paralysis of the v and vi cranial nerves. imaging studies were obtained to investigate an orbital apex and a cavernous sinus syndrome. a computerized tomography scan of the orbit was normal but a high-resolution magnetic resonance imaging demonstrated bilateral enlargement of the cavernous sinus. although primary lymphoma of the central nervous system is a rare condition, it should be considered in the differential diagnosis in immunocompromised patients who develop ocular motility abnormalities and imaging signs suggestive of infiltrative cavernous sinus lesions.