Ultrastructural study of neuronal and related tumors in the ventricles.

Intraventricular tumors may arise from a variety of cells in the region. There are some difficulties in diagnosing these tumors because of their histologically similar appearance. We analyzed intraventricular tumors, including central neurocytoma, oligodendroglioma, cerebral neuroblastoma, and cerebellar neuroblastoma, the neuronal characters of which were established based on their ultrastructural findings, except for oligodendroglioma. Central neurocytoma and cerebellar neuroblastoma showed synaptic formation, and cerebral neuroblastoma possessed immature neurites. Oligodendroglioma showed similar structures to that of a normal oligodendrocyte. Furthermore, we review the literature and evaluate the usefulness of analyzing ultrastructures.