RADIATION-THERAPY OF WELL-DIFFERENTIATED NEUROBLASTOMA AND CENTRAL NEUROCYTOMA

Background. Central neurocytoma is a rare intraventricular tumor with prominent neuronal differentiation. Although reported cases of this di sease are increasing, the clinical benefit of radiation therapy remain s unclear. Methods. From 1979 to 1990, two patients with central neuro cytoma and five with well-differentiated neuroblastomas received radia tion therapy. Five were men and two were women; the age at onset range d from 20 to 37 years (mean age, 25.6 years). The follow-up period ran ged from 14 to 134 months (median, 68 months). The initial histologic diagnosis was oligodendroglioma in five, ependymoma in one, and suspec ted central neurocytoma in one. Electron microscopic examination showe d numerous neuronal processes containing microtubules and membrane-bou nd neurosecretory granules. Well-formed synaptic junctions were observ ed in the two cases of central neurocytoma. All patients underwent par tial or subtotal tumor resection before radiation therapy (partial res ection in three and subtotal resection in four). Three patients receiv ed radiation therapy locally, up to 50-60 Gy. Four cases were treated with a combination of whole brain irradiation (32-40 Gy) and local irr adiation (20-32 Gy). Results. Treatment results were quite favorable, and all patients are alive and well without evidence of recurrence. Co mputed tomography studies showed that bulky residual tumors disappeare d from several months to 1 year after the completion of radiation ther apy. In a patient who had surgery again, significant vacuolar degenera tion was observed by light microscopic examination. Conclusions. A hig h level of radiosensitivity was confirmed, but additional data are req uired to clarify the clinical benefit of radiation therapy.