Ependymomas of childhood. II. Electron microscopic study

Electron-microscopic study of 13 ependymomas showed 3 basic types of cells. One type of cells has features typical of normal ependymal cells, the second type consists of cells resembling normal or reactive astrocytes, and the third type of cells is undifferentiated. The 3 types of cells are present in various proportions in every tumor. Generally speaking, the astrocyte-like cells are more frequently encountered than the ependymal cells. Undifferentiated cells are seen, in small numbers, in all forms of ependymoma but they are the dominant cell type in the ependymoblastomas.