Histopathologic features in the central nervous system of 400 acquired immunodeficiency syndrome cases: implications of rates of occurrence.

Histopathologic lesions in the central nervous system (CNS) of 400 autopsy cases of the acquired immunodeficiency syndrome (AIDS) collected from 1982 to 1990 were studied. Lesions most closely associated with human immunodeficiency virus (HIV) infection in the CNS (perivascular macrophages, nodular encephalomyelitis, diffuse leukoencephalopathy, necrotizing encephalitis, and long-tract degeneration) were found in 20% of the cases. The group of vascular and inflammatory lesions and of opportunistic infections was seen in 25% of cases. These two lesion groups were found together in 32% of cases, and none of these lesions was present in 23% of cases (most of the latter having no significant CNS lesions). Length of survival increased in the last group of 100 cases compared with the first 300 cases. The homosexual and bisexual risk groups showed continuously increasing lengths of survival for each category of HIV-associated CNS lesions throughout the study, while the lengths of survival in the other risk groups varied. Patients in the last group of 100 autopsy cases with any HIV-associated lesion survived longer than patients without these lesions. The AIDS patients with no CNS lesions had the shortest mean length of survival. The results suggest that although survival is prolonged as specific therapy is given, there is an increase in CNS lesions in AIDS patients with longer survival. This may indicate that CNS lesions in AIDS are generally dependent on systemic disease progression over many months as immune function decreases.