RESUMO
The authors studied the cerebral lesions in 29 cases of acute necrotizing encephalitis. Electron microscopy showed the presence of typical herpes virus particles in 24 cases. In 16 of them the virus had been isolated from specimens of the brain taken by biopsy and in 8 other cases from autopsy specimens. In 3 acute cases the search for the virus was negative and it was not carried out in the two cases with prolonged evolution. Only 6 patients have survived. Some peculiar varieties have beeen observed, i.e. two adolescents had temporal and almost entirely unilateral lesions, and two aged females had severely hemorrhagic necrotic areas which could have been confounded with vascular lesions. In these two later cases typical particles were present. Finally, one case showed within the same nuclei at once typical herpes virus particles and other viral structures of vermicular form, the origin of which could not be precised.