Case 119. 

Measles encephalitis (subacute sclerosing panencephalitis) (8 y-o M)
       
  Brain lesion featured by progressive mental retardation and myoclonus (history of measles in infancy)  
       

 

  Nuclear inclusions are formed in oligodendroglial cells (HE, high power). Inclusions are also infrequently seen in neurons, but never in astroglia.