Gamma knife radiosurgery of recurrent central neurocytomas: a preliminary report

Objectives-A series of three recurrent central neurocytomas treated by gamm a knife radiosurgery (GKRS), which were initially totally resected, are des cribed. Up to now, no reports exist on this treatment modality for this rar e tumour entity. Methods-Three male patients, aged between 20 and 25 years, presented with l arge intraventricular tumours. Total tumour removal was achieved by a singl e surgical procedure (one patient) or two operations (two patients). Neurop athological investigation showed a central neurocytoma, immunohistochemical ly all three tumours expressed a neuronal anti-genetic profile typical for neurocytomas, and the MIB-1 proliferation index ranged from 2.4% to 8.7%. E ach patient experienced a tumour recurrence after 5 to 6 years. The recurre nce was multifocal in two and a singular tumour mass in one patient. Gamma knife radiosurgery was performed. The tumours were enclosed within the 30% to 60% isodoseline, and delivered a tumour marginal dose of 9.6 to 16 Gy. D uring the follow up period, the patients were tested clinically and the vol ume of the tumours was measured on MRI. Results-Within follow up periods of 1 to 5 years, control MRI showed a sign ificant decrease of the tumour mass in all cases. None of the patients deve loped new neurological symptoms after GKRS. Two patients returned to work i n their previous employment, whereas one patient remained permanently disab led due to a pre-existing visual impairment and abducens palsy. Conclusion-GKRS proved to be a useful tool in the treatment of recurrent ce ntral neurocytomas. Tumour control and even tumour shrinkage can be achieve d with a single procedure and a low risk of morbidity.