A spectrum in the pathology of toxoplasmosis in patients with acquired immunodeficiency syndrome.

We describe a variety of toxoplasmic lesions in seven patients with the acquired immunodeficiency syndrome. The first patient had multiple small-intestinal ulcers associated with Toxoplasma tachyzoites and high antibody titers; he died of disseminated histoplasmosis. The second patient, who died of tuberculosis, also had an inactive chronic Toxoplasma infection, with tissue cysts in the brain that were associated with glial nodules. A third patient died of Toxoplasma encephalitis, manifested by multiple foci of necrosis associated with Toxoplasma tachyzoites, cysts, and hypertrophic arteritis. A fourth patient had been treated for toxoplasmic encephalitis with co-trimoxozol (trimethoprim-sulfamethoxazole combination) for 3 to 4 days and showed degenerating tachyzoites associated with necrotic areas. A fifth patient, treated for toxoplasmic encephalitis with co-trimoxazol for 14 days, had necrotic lesions associated with Toxoplasma antigen and a few cysts. A sixth patient with encephalitis and Toxoplasma tachyzoites and young cysts in the biopsy showed healed brain lesions after 22 days of treatment. A seventh patient, diagnosed radiologically and serologically with Toxoplasma encephalitis, was treated for 7 months; his ring-enhancing lesions subsided, and he died of a central nervous system lymphoma. Toxoplasma could not be isolated from the brain, although toxoplasmic DNA was detected in the brain and heart by polymerase chain reaction. The pathogenesis of the range of these lesions, their diagnosis, and the possibility of terminating Toxoplasma infection by prolonged chemotherapy are discussed.