A 29-year-old male was admitted with chronic headache on February 26, 1987, when there were no neurological deficits or physical abnormalities. Computed tomographic (CT) scans showed a mixed-density mass with no evidence of calcification in the left lateral ventricle, which was irregularly enhanced by contrast medium. Under a diagnosis of an intraventricular glial tumor, surgery was performed via a left transcortical-transventricular approach on March 31. The highly vascular, nodular tumor, originated from the lateral wall of the left lateral ventricle near the foramen of Monro, was successfully removed. The postoperative course was uneventful and he was discharged 3 months after postoperative irradiation. Light microscopic examination revealed the tumor cells with the clear cytoplasm and perinuclear halos characteristic of an oligodendroglioma. However, electron microscopy showed neuronal elements identical with central neurocytoma as reported by Hassoun et al. in 1982. These included large numbers of dense-core or clear vesicles in the cell processes and synaptic structures.