To determine the tumor control rates and endocrinological responses after stereotactic radiosurgery for pituitary adenomas, we reviewed our experience in 65 patients (40 men, 25 women) treated in the Gamma Knife during the last 4 years. The mean age was 41.6 years (range 19–69 years). 43 patients had endocrinologically active tumors (20 growth hormone-secreting, 19 prolactin-secreting and 4 ACTH-secreting adenomas). 22 had nonfunctioning adenomas. 39 patients had a macroadenoma and 26 patients had a microadenoma. 33 patients underwent Gamma Knife radiosurgery for recurrent or residual tumors after microsurgery. 50 patients have had follow-up neuroimaging studies and/or hormonal evaluation. The follow-up period was 25.5 months (range 3 to 54 months). The margin of the tumor was incorporated within the 50 to 90% isodose. The mean number of isocenters was 3.8 and the mean marginal dose was 25.4 Gy (range 15 to 36 Gy). 27 out of 40 patients (65.7%) showed decreased tumor volume to less than 50% of the initial volume. In 17 out of 38 patients (44.7%) with endocrinologically active tumors, the hormonal level fell to within the normal range. Two patients had delayed complications: in one case there was pituitary insufficiency and in the other a visual disturbance. Gamma Knife radiosurgery seems to be effective adjuvant therapy for pituitary adenoma in selected cases. More long-term follow-up is required to evaluate the efficacy and side effects further.

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The effect of radiosurgery on optic gliomas is uncertain. We report two cases of low-grade glioma of the optic nerve and chiasm treated by transcranial subtotal removal and Gamma Knife radiosurgery. The first case was a 2-year-old boy, admitted with visual disturbance and nystagmus. Histopathological examination showed a pilocytic astrocytoma. The tumor volume was 14.4 cm³. Dose planning was performed using axial and coronal Ti-weighted enhanced images. The marginal dose was 12 Gy at the 40% isodose line. The dose to the optic apparatus was less then 9 Gy. The second case was a 47-year-old woman, admitted to our hospital with headache and visual disturbance. The histopathological findings showed a fibrillary astrocytoma. The tumor volume was 12.3 cm³. The marginal dose was 14.4 Gy at the 40% isodose curve. The follow-up periods for the two cases were 24 and 43 months, respectively. In both cases the most recent follow-up magnetic resonance scan showed a marked decrease in tumor size, and visual symptoms were improved. No postradiosurgical complications have developed to date. Gamma Knife radiosurgery could be an effective adjuvant therapy for low-grade optic glioma. However, long-term follow-up is required for further evaluation of the efficacy and potential side effects.

A large meningioma in the cerebellopontine angle manifested itself as a contralateral hemifacial spasm. On computed tomographic and magnetic resonance imaging scans, the brain stem was markedly displaced and distorted by the tumor. After total removal of the meningioma, the hemifacial spasm completely disappeared.