[Clinico-pathologic case of slowly progressive herpes simplex encephalitis without temporal necrosis]

A case of herpes simplex encephalitis (HSE) is reported. The patient experienced short term memory disorders and irritability progressing over 3 months, without seizures or fever. The CSF was normal. CT showed a small low density area in the right posterior orbito-frontal region. At post-mortem examination, one month later, the temporal cortex appeared largely spared by necrosis, which involved the posterior orbito-frontal areas. Cowdry type A inclusions, herpes virus like particles and fluorescent reaction with HSV1 monoclonal antibodies strongly supported the diagnostic. Such atypical cases of long duration have apparently seldom been reported. They suggest that HSE should be considered in the differential diagnosis of a subacute encephalopathy.