Radiosurgery for radiosurgery-induced cavernous malformation

Background This report describes the use of radiosurgery for the treatment of a radiosurgery-induced cavernous malformation (CM). Methods A 21-year-old woman underwent stereotactic biopsy of a pineocytoma and subsequent gamma knife radiosurgery (marginal 14.5 Gy, 50%) for the lesion. A T1-weighted enhanced magnetic resonance imaging one year later showed that the tumor had disappeared. After two years, she developed facial palsy and experienced mental status changes. It was found that she experienced repeated hemorrhages in that radiation field, and magnetic resonance imaging showed a CM. Results The area where the CM developed had been exposed to 5.0 ± 3.7 Gy. This value was calculated using the fused dose planning image using Leksell GammaPlan. We used gamma knife radiosurgery to treat this lesion (marginal 12.5 Gy, 50%), and believe that it is a radiation-induced CM. Five years after gamma knife radiosurgery for the CM, the CM has controlled without any new hemorrhages. Conclusions Gamma knife radiosurgery-induced CMs are very rare, and the use of another gamma knife radiosurgery to treat this lesion has not yet been reported. We report a case of radiosurgery for CM that was induced by gamma knife radiosurgery for a pineocytoma. This report suggests that radiosurgery is a reasonable option for treating radiation-induced CM to prevent repeated hemorrhage.