HISTOPATHOLOGY OF CEREBRAL TOXOPLASMOSIS IN HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION - A COMPARISON BETWEEN PATIENTS WITH EARLY-ONSET AND LATE-ONSET ACQUIRED-IMMUNODEFICIENCY-SYNDROME

We reviewed the histological features of untreated toxoplasmosis in 18 cases with the acquired immunodeficiency syndrome (AIDS), eight of wh ich were surgical biopsies and 10 of which were autopsy specimens. The results were compared according to the clinical status of the patient at the time the diagnosis of toxoplasmosis was made (early-onset v la te-onset AIDS) and according to the source of the specimen (surgical b iopsy specimen v autopsy specimen). Cerebral toxoplasmosis was the AID S-defining illness in half of the cases (six surgical biopsy specimens and three autopsy specimens). Inflammation in these cases was moderat e in 44% and severe in 56%. Fibrous capsules were found in five Eases. Lymphocytes and plasma cells were more prominent than neutrophils. Ce rebral toxoplasmosis developed in or was,part of the terminal AIDS ill ness in the remaining nine cases (two surgical biopsy specimens and se ven autopsy specimens). In this group inflammation was sparse in 44%, moderate in 55%, and severe in only 11%. Fibrous capsules were usually absent and neutrophils were the predominant cell type. Comparisons be tween surgical biopsy specimens and autopsy specimens showed moderate to severe inflammation and frequent fibrous encapsulation in all of th e former specimens but only in those autopsy specimens in which toxopl asmosis was the initial manifestation of AIDS. Thus, this study demons trates varied neuropathological patterns of untreated cerebral toxopla smosis in patients with AIDS and correlates the inflammatory response in the brain with the clinical stage of the patient's human immunodefi ciency syndrome (HIV) infection. Inflammation and fibrous encapsulatio n were common only in patients with early-onset AIDS in whom cerebral toxoplasmosis was the first manifestation of the illness. This study h ighlights important differences between the histology of this infectio n at surgical biopsy and at autopsy, and stresses the need to consider toxoplasma as a potential cause of encapsulated brain abscesses. Copy right (C) 1994 by W.B, Saunders Company