New variant of persistent primitive olfactory artery associated with a ruptured aneurysm.

The authors present the case of a 78-year-old man who presented with a subarachnoid hemorrhage due to rupture of an aneurysm at the origin of the persistent primitive olfactory artery (PPOA). Interestingly, the PPOA was originating from the A1 segment of the anterior cerebral artery and coursed anteromedially along the olfactory tract. Moreover, the PPOA in this case had 2 branches: the branch making a hairpin turn and supplying the distal part of the anterior cerebral artery territory (Type 1), and the branch extending to the cribriform plate to supply the nasal cavity (Type 2). To the best of the authors' knowledge, this is a new variant (Type 3) of PPOA associated with a ruptured aneurysm. The clinical implications of this case are discussed in terms of the embryological aspects.