Herpes simplex encephalitis and sarcoidosis.

Fatal herpes simplex encephalitis occurring in a patient with sarcoidosis is described. Ultrastructural study of brain tissue revealed the presence of herpesvirus particles. The association of these 2 diseases has not been recorded before. The encephalitis in this case probably represents an opportunistic viral infection in the face of depressed cellular immunity. Progressive multifocal leukoencephalopathy, a disease of putative viral aetiology, is known to occur in patients with sarcoidosis and it is suggested that this case represents a similar pathogenetic association.