Cytomegalovirus encephalitis in patients with acquired immunodeficiency syndrome: an autopsy study of 30 cases and a review of the literature.

The pathology of cytomegalovirus (CMV) encephalitis was studied at autopsy in thirty patients with acquired immunodeficiency syndrome. Lesions could be segregated into five major categories: microglial nodules, isolated inclusion-bearing cells, focal parenchymal necrosis, necrotizing ventriculo-encephalitis, and necrotizing radiculo-myelitis. Microglial nodules and CMV inclusions were present in all brains. Microglial nodules were found with variable frequency and had greatest density in subcortical grey matter. Only a small percentage (average, 6.5 per cent) contained CMV inclusion-bearing cells. Isolated inclusion-bearing cells unaccompanied by microglial nodules or inflammatory infiltrates were seen in half the patients. CMV inclusions were identified in capillary endothelia, astrocytes, and neurons. Focal CMV necrosis, ventriculo-encephalitis, and radiculo-myelitis were less frequent. The presence of CMV inclusions in capillary endothelia suggests a vascular portal of entry for the virus into the central nervous system. The diffuse ependymal and/or subpial distribution of CMV in several patients suggests additional dissemination via the cerebrospinal fluid. Isolated inclusion-bearing cells may reflect the relative nonpermissiveness of surrounding central nervous system parenchyma for CMV infection.