Radiation therapy of well-differentiated neuroblastoma and central neurocytoma.

Abstract

Central neurocytoma is a rare intraventricular tumor with prominent neuronal differentiation. Although reported cases of this disease are increasing, the clinical benefit of radiation therapy remains unclear. From 1979 to 1990, two patients with central neurocytoma and five with well-differentiated neuroblastomas received radiation therapy. Five were men and two were women; the age at onset ranged from 20 to 37 years (mean age, 25.6 years). The follow-up period ranged from 14 to 134 months (median, 68 months). The initial histologic diagnosis was oligodendroglioma in five, ependymoma in one, and suspected central neurocytoma in one. Electron microscopic examination showed numerous neuronal processes containing microtubules and membrane-bound neurosecretory granules. Well-formed synaptic junctions were observed in the two cases of central neurocytoma. All patients underwent partial or subtotal tumor resection before radiation therapy (partial resection in three and subtotal resection in four). Three patients received radiation therapy locally, up to 50-60 Gy. Four cases were treated with a combination of whole brain irradiation (32-40 Gy) and local irradiation (20-32 Gy). Treatment results were quite favorable, and all patients are alive and well without evidence of recurrence. Computed tomography studies showed that bulky residual tumors disappeared from several months to 1 year after the completion of radiation therapy. In a patient who had surgery again, significant vacuolar degeneration was observed by light microscopic examination. A high level of radiosensitivity was confirmed, but additional data are required to clarify the clinical benefit of radiation therapy.