A 48 year-old woman developed headaches followed by spells of intermittent double vision and facial numbness.

Axial CT scan. Note the large fusiform aneurysm affecting both the left vertebral and basilar arteries. Although aneurysms typically come to clinical attention by bleeding, rarely they will enlarge and result in a mass lesion..

Revised05/01/06.
The Electronic Curriculum is copyrighted 1998,  Case Western Reserve University School of Medicine.