A rare case report: bilateral occipital artery arising from the vertebral artery

Variations of the origin of the occipital artery (OA) can be considered as congenital anomalies that are often asymptomatic and detected incidentally on angiography or during cadaver dissection. While OA normally originates from the posterior aspect of the external carotid artery (ECA), recent evidence also reflects that OA may infrequently originate from the internal carotid artery (ICA); however, OA originating from the vertebral artery (VA) is a highly rare phenomenon.

In a 54-year-old female patient with the complaint of left hemiparesis, computed tomography (CT) angiography revealed nonstenotic calcified plaques at the beginning of right ICA where common carotid artery (CCA) bifurcates. We also incidentally observed that bilateral OA originated from the VA using maximum intensity projection (MIP) technique. In addition to this rare variation, CT angiography showed the osseous anomaly termed as high-riding VA (HRVA) in the C1/2 vertebral space of the V3 segment of the VA.

To the best of our knowledge, a case of bilateral OA originating from the VA has not been reported to date. We believe that recognition of this rare variation may contribute to the relevant literature and it is of importance to consider this variation in radiological imaging and surgical procedures involving this region.