Left common carotid artery agenesis with separate origins of internal and external carotid arteries

Absent left common carotid artery in a right aortic arch: Separate origins of left internal and external carotid arteries from brachiocephalic artery

“…Anomalies of supra‐aortic branch vessels are well described in the literature with agenesis or absence of CCA being extremely rare. In a left‐sided aortic arch, if CCA is absent on the right side, the ICA and ECA arise from BCA, whereas if the CCA is absent on the left side, both these arteries arise from the aortic arch directly 1,2 . Although, one of the associations of an absent CCA is a right aortic arch, the simultaneous occurrence of a right aortic arch, an absent left CCA with both ICA and ECA arising from BCA and cyanotic congenital heart disease (CHD) is extremely uncommon.…”

“…In a left-sided aortic arch, if CCA is absent on the right side, the ICA and ECA arise from BCA, whereas if the CCA is absent on the left side, both these arteries arise from the aortic arch directly. 1,2 Although, one of the associations of an absent CCA is a right aortic arch, the simultaneous occurrence of a right aortic arch, an absent left CCA with both ICA and ECA arising from BCA and cyanotic congenital heart disease (CHD) is extremely uncommon. Potential F I G U R E 1 Volume rendered images (A and B) reveal the presence of a right-sided aortic arch with the first branch being the left brachiocephalic artery (BCA) with separate origins of the left external carotid artery (ECA) and left internal carotid artery (ICA) from it F I G U R E 2 Volume rendered image (A) and axial image (B) shows separate left external carotid artery (ECA) and left internal carotid artery (ICA) with the ECA being anteromedial to the ICA.…”

Separate arch origin of the left external carotid artery with common trunk giving rise to the left internal carotid artery and left subclavian artery

“…Interestingly, in our patient, there was a common trunk giving rise to left internal carotid artery and left subclavian artery with the direct origin of the left external carotid artery from the arch. Embryologically, in the absence of a cervical aortic arch, this pattern may result secondary to the persistence of left‐sided carotid duct along with involution of the left third pharyngeal arch artery 1,2 . In a right aortic arch, this results in separate origin of left internal and external carotid artery from the brachiocephalic artery 3 .…”

“…Embryologically, in the absence of a cervical aortic arch, this pattern may result secondary to the persistence of left-sided carotid duct along with involution of the left third pharyngeal arch artery. 1,2 In a right aortic arch, this results in separate origin of left internal and external carotid artery from the brachiocephalic artery. 3 We hypothesize that in our patient, additional migration of the left external carotid artery laterally on to the arch resulted in its separate origin from the arch with a common trunk giving rise to the left internal carotid artery and left subclavian artery (instead of the brachiocephalic artery).…”