Toxoplasmosis of the conus medullaris in a patient with hemophilia A-associated AIDS. Case report. Toxoplasma gondii has been reported to be the most common cause of focal brain lesions in patients with acquired immunodeficiency syndrome (AIDS). A case of intramedullary toxoplasmosis of the conus medullaris is reported in a patient with hemophilia A-associated AIDS. The diagnosis is discussed, with particular emphasis on the magnetic resonance imaging appearance. 