Case 121. 

JC virus infection (progressive multifocal leukoencephalopathy) (35 y-o F)
　 　 　 　
　 Progressive deterioration of brain functions in case of SLE receiving corticosteroid 　
　 　 　 　

　

 　 Oligodendroglial cells contain pyknotic nuclei and nuclear inclusion bodies. Reactive astroglial cells are seen (LFB-HE, high power).