The ultrastructure of the nervous tissue in a benign teratoma.

The ultrastructure of the nervous tissue in a benign ovarian teratoma is described. This tissue was organized into areas having both "meningeal" and "ependymal" surfaces, between which were found astrocytes, ependymal cells, neurones with synapses and microglia. These cells all had ultrastructural similarities to their normal counterparts in the nervous system. In addition, some signs of degenerative change--due possibly to the abnormal location of the nervous tissue--were observed. Oligodendrocytes and myelin were absent, possibly because of vascular insufficiency.