Unusually Located Proximal Middle Cerebral Artery Saccular Aneurysm.

Middle cerebral aneurysms constitute almost one-third of all anterior circulation aneurysms. Most of the saccular aneurysms originate from the arterial branching sites, but origins other than at the branching site are extremely rare. In this article, we are describing a unique M1 segment middle cerebral artery aneurysm which is not related with any branching site. Our literature search suggests that atherosclerotic changes in the arterial wall and local hemodynamic forces play an important role in the development of these types of aneurysm. Surgical management is not so unique in this type of aneurysm, but due to atherosclerotic parent arterial wall and thin-walled aneurysm sac, a neurosurgeon should be more cautious.