Cyst of the intraorbital optic nerve sheaths

A 43-year-old woman had a history of gradual unilateral visual acuity loss and proptosis. A 2.5-cm cystic dilatation of the intraorbital dura mater was removed. Microscopic examination revealed a vascular proliferation within the leptomeninges. We inadvertently injected the lesion during orbitography, providing us with an unusual radiographic appearance.