A hypoplastic right vertebral artery (VA), a complete circle of Willis with hypoplastic right P1- and A1-segments, and left dominant arterial configuration were incidentally detected in a 75-year-old male donor. The P1- segment of the left posterior cerebral artery (PCA) gave branch to an accessory right posterior cerebral artery (APCA). The hypoplastic right A1-segment arose from the right middle cerebral artery (MCA). The right posterior communicating artery (PCoA) from the smaller right internal carotid artery (ICA) continued as the right P2-segment. The larger left ICA gave branch to the dominant left anterior cerebral artery (ACA) from which the anterior communicating artery (ACoA) and both the left and right A2 –segments arose. Due to the well stablished close association of vascular dominance and variations with cerebrovascular diseases, the knowledge of the variable vascular architecture at the base of the brain, would be imperative in the various diagnostic and therapeutic procedures.
