[Two Cases of Venous Malformation of the Orbit Treated by Endoscopic Endonasal Surgery].

Venous malformation of the orbit(VMO), previously called orbital cavernous hemangioma, has been classified as a vascular malformation according to the International Society for the Study of Vascular Anomalies. Among various surgical approaches for VMO, endoscopic endonasal surgery(EES)has recently been developed, especially for those in the inferomedial quadrant of the orbit. Two 67-year-old and 69-year-old women presented with decreased visual acuity and visual field deficit, respectively. Their CT and MRI scans revealed retrobulbar masses, suggestive of the inferomedial type of VMO. The first case was diagnosed as an intraconal VMO, and subtotal removal was achieved through binostril EES using a two-surgeon four-handed technique after palliative partial resection through a prior frontal craniotomy. In the second case, diagnosed as an extraconal VMO, total en bloc removal was achieved using the same surgical technique as above. In both cases, the visual functions improved after the procedures, with uneventful postoperative courses. Although the inferomedial VMO is an uncommon type, EES is well indicated for this condition. The international consensus of surgical techniques and staging from a surgical point of view should be established in the near future.