Fig. 3

Intraoperative photographs demonstrating an intradural extramedullary mass lesion which has a remarkable vascular grape-like dark red mass (a) and the sandy calcification in it (b). Although no tight adhesion was found between the tumor and the medulla oblongata, the lesion adhered robustly to the wall of vertebral artery (c). Post-tumor resection view, accessory nerve and C1 root were totally preserved (d). MO medulla oblongata, T tumor, VA vertebral artery