Successful resection of large subependymal giant cell astrocytoma using presurgical mammalian target of rapamycin inhibitor.

Background: A subependymal giant cell astrocytoma (SEGA) grows slowly near the foramen of Monro and develops in tuberous sclerosis complex patients. Large SEGA resection has a high risk of hemorrhage, resulting in irreversible sequelae. Mammalian target of rapamycin (mTOR) inhibitor has been approved for the treatment of SEGA which cannot be curatively treated surgically.

Case description: An 8-year-old boy was found to have two nodules beside bilateral ventricles. After the interruption of regular examination, he was transported to the hospital with seizure, headache, and visual impairment caused by hydrocephalus. Computed tomography (CT) scan revealed two masses: one at each the left (60 × 50 × 60 mm) and right (20 × 10 × 10 mm) ventricles. An emergency ventricular outside shunt was placed, but reduction surgery could not be performed. Everolimus at 3 mg/m² was orally administered as preoperative therapy. A reduction in tumor size was observed 2 months after everolimus initiation. Reduction surgery for the right-sided tumor was performed after discontinuation of the drug. The tumor at the left septum lucidum and caudate nucleus remained. Everolimus was administered again for residual tumor growth. After a series of surgeries, complete resection of both tumors was performed eventually.

Conclusion: This report shows preoperative treatment using mTOR inhibitor to be an effective strategy for unresectable large SEGA.