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) 　
　 　 　 　

　

 　 Electron micrograph of the nuclear inclusion in an oligodendrocyte. Elongated, spiral or rod-like tubules, 15 nm in diameter and 5 nm in the inner space, occupy the nuclear matrix. Measles virus causing SSPE is defective of M (matrix) protein.