Recurrent astroblastoma treated with gamma knife radiosurgery.

Astroblastomas are exceedingly rare central nervous system tumors. Surgical resection is the standard initial treatment for astroblastomas. Still, some astroblastomas that have been completely resected recur. The optimal treatment for these lesions is unclear. There are no previous reports of the use of Gamma Knife radiosurgery in the treatment of astroblastomas. The patient is a 58 year old woman who had undergone resection of a left parieto-occipital tumor at an outside hospital in 2002, with repeat resection for recurrences in 2005 and 2007. Pathologic analysis at the Mayo Clinic demonstrated the tumor to be a low-grade astroblastoma. Repeat imaging in 2008 again demonstrated recurrence, and the patient was referred to our center for Gamma Knife radiosurgery. Pre and post-contrast T1 stereotactic MR images were obtained and imported into the treatment planning system for the Gamma Knife Perfexion. Two foci of tumor consistent with the patient's known left parietal astroblastoma were identified. A prescription dose of 18.00 Gy to the 50% isodose was delivered, and 16 isocenters were used. Follow-up imaging 17 months post-radiosurgery demonstrated a decrease in tumor size. Gamma Knife radiosurgery represents a useful treatment modality for recurrent astroblastomas. While surgical resection of low grade astroblastomas can be curative, Gamma Knife radiosurgery may be beneficial in cases where gross total resection is not feasible.