Gamma knife radiosurgery for central neurocytomas.

The long-term outcome of gamma knife radiosurgery (GKS) for central neurocytomas remains unclear. In the present study, we retrospectively reviewed the medical records of 7 patients with 8 central neurocytomas who underwent GKS between March 1997 and April 2007. They were 3 men and 4 women age ranging 9 to 53 years old (mean 32.5 years old). The tumor volume at the time of GKS was 0.34-6.10 cm(3) (mean 3.86 cm(3)). All patients had undergone 1 to 3 incomplete surgical resections (mean 1.75) before GKS, the surgical specimen being evaluated histologically and immunohistochemically. The follow-up period after GKS was 15 to 136 months (mean 63.6 months). The tumors were treated with a marginal dose of 12-18 Gy (mean 13.9 Gy). Only one of the seven patients died of tumor recurrence and intracranial hemorrhage 40 months after GKS. The other tumors remained progression-free. The control rate of the tumor growth was 7/8. Although histological malignant transformation is rare, the postoperative course of this tumor is not always good, showing tumor progression, intracranial hemorrhage, or craniospinal dissemination. Therefore, we recommend GKS for residual or recurrent tumors especially at early detection before tumor progression.