Fenestration of the superior cerebellar artery diagnosed by magnetic resonance angiography.

We herein report a case of fenestration of the superior cerebellar artery (SCA), which was incidentally diagnosed by magnetic resonance (MR) angiography. A 65-year-old woman was referred to our hospital for unruptured cerebral aneurysms. MR angiography revealed 2 unruptured aneurysms. It also showed fenestration of the left SCA near its origin from the basilar artery, as well as several other vascular variations: a left common carotid artery arising from the brachiocephalic trunk, and a right vertebral artery terminating to the right posterior inferior cerebellar artery. Yearly observation was chosen as a treatment strategy due to the small size of the cerebral aneurysms. According to previous reports, SCA fenestration is an extremely rare variation. This is the second case of SCA fenestration diagnosed by MR angiography in the relevant English-language literature.