Isolated homonymous lateral hemianopsia revealing central nervous system toxoplasmosis as the initial manifestation of AIDS.

A 25-year-old-healthy man, with previous history of parenteral drug abuse, developed a left homonymous hemianopsia. Computed tomographic scanning showed a single ring enhancing lesion in the right parieto-occipital area. After the demonstration of seropositivity for human immunodeficiency virus and high serum immunoglobulin G antibody titer against Toxoplasma gondii, a diagnosis of cerebral toxoplasmosis in an AIDS patient was made. An isolated visual field defect revealing cerebral toxoplasmosis may be the first presentation of AIDS. Opportunistic cerebral lesions should be always considered in subjects at risk for AIDS who present focal neurological signs.