Mirror Meningioma at Foramen Magnum: A Management Challenge.

Abstract

Meningiomas of the foramen magnum are among the most challenging of all skull base lesions. Controversies continue regarding the most appropriate approach to this critical anatomic region. The authors report a first case in English literature about twin meningiomas arising from both sides of the ventrolateral dura at the foramen magnum. Preoperative imaging showed a solitary mass engulfing the lower medulla. However, intraoperatively a twin mass was discovered. It encased the right side vertebral artery (VA) and abutted the left side. The unilateral far lateral transcondylar approach is not enough to resect both tumors at the same time. However, the far lateral transcondylar approach in both sides may compromise the stability and increase the risk of injury to either side of the neurovascular structures. We suggest that resection can be safely achieved via the unilateral far lateral transcondylar approach followed by Gamma Knife radiosurgery (GKRS) or a staged bilateral approach.