[A case of basilar artery occlusion caused by vertebrobasilar artery dissection presenting with mild clinical symptoms].

We reported a first case of basilar artery occlusion caused by vertebrobasilar artery dissection presenting with mild clinical symptoms. A 45-year-old female was admitted to our department due to the abrupt onset of pain in her posterior neck and occipital head, and numbness in the right upper and lower extremities. She had no other neurological complaints. Computerized tomography and magnetic resonance imaging (MRI) disclosed no abnormalities in parenchyma, but MRI revealed a linear high intensity structure in front of the medulla oblongata on T1 and T2 weighted images. Cerebral angiogram showed the pearl and string sign from the left vertebral artery to the proximal basilar artery, and showed the basilar artery occlusion, but the basilar artery distal to the occlusion site was perfused sufficiently by the carotid via posterior communicating arteries. We diagnosed it as basilar artery occlusion caused by vertebrobasilar artery dissection, which was confirmed during the operation to prevent a hemorrhage from the aneurysmal dilatation. In this case, collateral good circulation was thought to have contributed to her good clinical course.