Presurgical Administration of mTOR Inhibitors in Patients with Large Subependymal Giant Cell Astrocytoma Associated with Tuberous Sclerosis Complex

BACKGROUND: Direct surgical resection remains the standard treatment for patients with tuberous sclerosis complex (TSC) with a large subependymal giant cell astrocytoma (SEGA). Rapamycin or everolimus is seldom used in these patients because of the risk of increased intracranial pressure and possibility of sudden death. CASE DESCRIPTIONS: Three patients with TSC and a large intracranial SEGA received oral rapamycin (0.5 mg/day) or everolimus (2.5 mg/day) before surgery for tumor resection. After mTOR inhibitor therapy, computed tomography scans and magnetic resonance imaging revealed tumor reduction. Tumor bleeding was easy to control during surgery, and the border between tumor and surrounding brain tissue was clearly differentiated. Analysis of postsurgical tumor specimens showed low blood density and focal necrosis. CONCLUSIONS: Preoperative mTOR inhibitors could be a potentially novel treatment modality in large TSC-SEGA with hydrocephalus. In this series, mTOR inhibitors were not only safe and well tolerated, but also beneficial for tumor resection.