A patient with AIDS-related complex (ARC) presented with a fulminant neurologic syndrome suggestive of ascending myelopathy, and died approximately 48 h after admission to hospital. At necropsy, there was evidence of a severe necrotizing vasculitis affecting the nervous system most severely, with multifocal haemorrhagic necroses of the spinal cord and cauda equina. Although a rare intranuclear inclusion suggestive of herpesvirus infection was seen in the predominantly lympho-histiocytic infiltrate in and around blood vessel walls, the precise aetiology of the angiitis was not apparent. It may represent a response to AIDS virus infection of one or more components of the blood vessel wall.