[Electron microscopy of 300 tumors in the nervous system].

The results of 300 nervous system tumors observed by electron microscopy are reported. Of them, 12% depended on electron microscopy for diagnosis; 14% was further classified and typed by electron microscopy; 59% could be diagnosed by either electron or light microscopy but the former played an important role in confirming the diagnosis by light microscopy; 10% still could not be diagnosed even by electron microscopy; 5% failed in diagnosis due to faulty technique. The results indicate that the electron microscope is a useful tool in diagnosis of the nervous system tumor, particularly, in those whose diagnosis is difficult by light microscopy and in classification and typing of the tumor. In this paper, the pathognomonic ultrastructural features are described.