Figure 2.

Intraoperative endoscopic view showing: (a) The bone of the anterior skull base was removed with a high-speed diamond drill during debulking of the extradural tumor; (b) the dura of the anterior skull base surrounding the tumor margin was exposed after removal of the bone of the anterior skull base; (c) The posterior margin of the tumor, left optic nerve, and left internal carotid artery was exposed after removal of the extradural tumor; (d) Incising the dura of the anterior skull base along the tumor margin; (e) Endoscopic endonasal view of the surface of the brain and intradural residual tumor during removal of the intradural tumor; (f) The brain descended after complete removal of the intradural tumor. T: Tumor; D: Dura; Su: Suction; LON: Left optic nerve; L-ICA: Left-internal carotid artery; K: Knife; B: Brain; CP: Cribriform plate: Dr: Drill; PS: Planum sphenoidale; LP: Lamina papyracea; FS: Frontal sinus.