Peritumoral edema following Gamma Knife radiosurgery as the primary treatment for intraventricular meningiomas.

Intraventricular meningiomas represent a small proportion of intracranial meningiomas. Stereotactic radiosurgery (SRS) as a primary treatment for intraventricular meningiomas has been reported only recently. We present two patients with trigonal meningiomas who developed peritumoral edema 5months and 12months following SRS. The patients' inability to wean off corticosteroids and progressive worsening of neurologic symptoms required eventual microsurgical resection of the intraventricular tumors. Follow-up MRI at 3 and 4 years after surgery demonstrated no evidence of tumor recurrence. Reports of patients with ventricular meningiomas treated primarily with Gamma Knife radiosurgery are sparse. To our knowledge, this is the first report of the development of extensive peritumoral edema following SRS for intraventricular meningioma. Larger case series with longer follow-up are required to define the incidence and timing of edema formation surrounding intraventricular meningiomas following treatment with radiosurgery.