Background.- Subacute sclerosing panencephalitis (SSPE) is a very rare and fatal complication of measles infection which is seen 2 to 21 years after initial infection. The incidence of SSPE is 1/ 300.000.
Observation.- A 25 years old case with SSPE was presented. He had clinical and radiological evidence of progressive brain involvement. The stereotactic brain biopsy revealed secondary demiyelination, lymphocytic cuffing, viral inclusion within oligodendroglia and neurons which showed immunhistochemically positive reaction with measles virus primary antibody. The differential diagnosis was made between the other viral encephalitis and the literature was reviewed.