Treatment of intracranial solitary fibrous tumors with gamma knife radiosurgery: report of two cases and review of literature.

Abstract

Gamma knife radiosurgery (GKRS) as a treatment option has not been described in the management of typical intracranial solitary fibrous tumors. After presenting with visual decline, case A underwent a bioccipital craniotomy during which 90% of tumor was thought to have been resected. She unfortunately required re-resection 56 months later for recurrence when she again presented with progressive visual decline, altered mental status, and headaches. A subtotal resection was performed, because there was extensive tumor involvement of the torcula, straight sinus, and bilateral transverse sinuses. She was subsequently referred for GKRS. Although neurologically intact, with the exception of an upper extremity tremor, case B had undergone 7 surgeries for a posterior fossa tumor over the several decades preceding GKRS. The tumors targeted with GKRS were found on serial MRI scans and were thought to be asymptomatic at the time of treatment. At 7 and 14 months after GKRS, case A experienced tumor shrinkage, which remained stable 20 months after treatment. Effective local tumor control was seen in case B with tumor shrinkage at 3, 8, and 13 months after treatment. However, repeat GKRS was required for case B, because an out-of-field recurrence was found 15 months after the initial GKRS. Based on this report and available information in the literature, radiosurgery appears to be a reasonable approach for patients with recurrent or residual intracranial solitary fibrous tumors.