AGENESIS OF THE INTERNAL CAROTID ARTERY - COLLATERAL VASCULARIZATION AND SYMPTOMATIC MANIFESTATIONS
Abstract
Introduction and objective: Internal carotid artery agenesis is a rare anatomical anomaly involving the absence of the internal carotid artery. It is a congenital developmental defect that can present with varying symptoms depending on whether it is unilateral or bilateral. The aim of this article is to summarize the diversity and prevalence of symptoms associated with unilateral or bilateral agenesis of the internal carotid artery.
Methodology: In the literature review, scientific works related to internal carotid artery agenesis were utilized, including 26 studies addressing the described variability, which collectively encompass 52 cases of patients with internal carotid artery agenesis. After a thorough analysis of the cited literature, conclusions were drawn regarding the frequency and relationships between unilateral and bilateral absence of the ICA.
Discussion: Agenesis of the internal carotid artery is a rare anomaly; however, its detection is crucial in the diagnosis of cerebrovascular disorders. Among symptomatic patients with internal carotid artery agenesis, intracranial aneurysms leading to subarachnoid hemorrhages were frequently observed. Additionally, collateral pathways replacing its blood flow, such as perineural anastomoses, and alterations in the normal course of other vessels in the neck and head region were also noted.
Conclusions: Agenesis of the ICA occurs in 0.01% of cases and is additionally associated with the absence of the carotid canal, through which the artery typically traverses. It is more commonly seen as left-sided agenesis of the ICA, with bilateral agenesis occurring in less than 10% of cases. 25% of cases of internal carotid artery agenesis are associated with intracranial aneurysms. The majority of symptomatic patients are between 35 and 65 years of age. Patients with internal carotid artery agenesis most frequently exhibit neurological disorders as well as nonspecific symptoms such as headaches and nausea.
References
Bochenek, A., & Reicher, M. (n.d.). Human anatomy (Vol. 3).
Erdogan, M., Senadim, S., & Ince Yasinoglu, K. N. (2017). Internal carotid artery agenesis with an intercavernous anastomosis: A rare case. Journal of Stroke and Cerebrovascular Diseases, 26(10), 2442–2445. https://doi.org/10.1016/j.jstrokecerebrovasdis.2017.06.055
Bergman, R. A., Afifi, A. K., & Miyauchi, R. (n.d.). Bergman’s comprehensive encyclopedia of human anatomic variation.
Kulhari, A., Singh, A., & Fourcand, F. (2023). Internal carotid artery agenesis: A rare entity. Cureus, 15(3), e36640. https://doi.org/10.7759/cureus.36640
Kaya, O., Yilmaz, C., & Gulek, B. (2014). An important clue in the sonographic diagnosis of internal carotid artery agenesis: Ipsilateral common carotid artery hypoplasia. Case Reports in Radiology, 2014, 516456. https://doi.org/10.1155/2014/516456
Cohen, J. E., Gomori, J. M., & Leker, R. R. (2010). Internal carotid artery agenesis: Diagnosis, clinical spectrum, associated conditions and its importance in the era of stroke interventions. Neurological Research, 32(10), 1027–1032. https://doi.org/10.1179/016164110X12767786356273
Sonne, J. W., Kaiser, H., & Williams, S. (2021). Absent internal carotid artery with intact circle of Willis. Cureus, 13(8), e17090. https://doi.org/10.7759/cureus.17090
Clarós, P., Bandos, R., & Gilea, I. (1999). Major congenital anomalies of the internal carotid artery: Agenesis, aplasia and hypoplasia. International Journal of Pediatric Otorhinolaryngology, 49(1), 69–76. https://doi.org/10.1016/s0165-5876(99)00012-9
Liau, Y. J., Jabbour, A. J., & Yerdon, H. (2023). Bilateral internal carotid artery agenesis in a patient with a family history of intracranial pathology. Ochsner Journal, 23(1), 88–91. https://doi.org/10.31486/toj.22.0052
Xu, X., Shen, H., & Ma, H. (2022). Cerebrovascular disorders associated with agenesis of the internal carotid artery: Findings on digital subtraction angiography. Frontiers in Surgery, 9, 953697. https://doi.org/10.3389/fsurg.2022.953697
Kim, M. S., Lee, S. J., & Lee, C. H. (2006). Bilateral segmental absence of the internal carotid artery with rete compensation associated with absence of basilar artery: Case report. Surgical Neurology, 65(6), 615–619. https://doi.org/10.1016/j.surneu.2005.07.072
Augusto, R., Coelho, N., & Semião, A. C. (2022). Right aortic arch associated with agenesis of the left internal carotid artery – An extremely rare case report. Portuguese Journal of Cardiac Thoracic and Vascular Surgery, 29(1), 75–79. https://doi.org/10.48729/pjctvs.148
Takamiya, S., Yoshimoto, T., & Maruichi, K. (2021). Cerebral aneurysms with internal carotid artery agenesis: A unique case similar to Moyamoya disease and literature review. Neurologia Medico-Chirurgica, 61(5), 321–333. https://doi.org/10.2176/nmc.oa.2020-0358
Elwood, K. F., Taboada, J. L., & Wong, R. W. (2019). Ocular ischemic syndrome with congenital absence of internal carotid artery. Journal of VitreoRetinal Diseases, 4(1), 79–83. https://doi.org/10.1177/2474126419866136
Lee, J. H., Oh, C. W., & Lee, S. H. (2003). Aplasia of the internal carotid artery. Acta Neurochirurgica, 145(2), 117–125. https://doi.org/10.1007/s00701-002-1046-y
Florio, F., Balzano, S., & Nardella, M. (1999). Congenital absence of the internal carotid artery. Cardiovascular and Interventional Radiology, 22(1), 74–78. https://doi.org/10.1007/s002709900334
Farhat, W., Ahdab, R., & Hosseini, H. (2011). Congenital agenesis of internal carotid artery with ipsilateral Horner presenting as focal neurological symptoms. Vascular Health and Risk Management, 7, 37–40. https://doi.org/10.2147/VHRM.S16642
Hüttemann, K., Nowe, T., & Engelhorn, T. (2008). Ischemic stroke and subarachnoid hemorrhage, two sides of a story: Congenital absence of the internal carotid artery. Two cases and review of the literature. Journal of Neurology, 255(12), 1985–1987. https://doi.org/10.1007/s00415-009-0071-7
Given, C. A., Huang-Hellinger, F., & Baker, M. D. (2001). Congenital absence of the internal carotid artery: Case reports and review of the collateral circulation. American Journal of Neuroradiology, 22(10), 1953–1959.
Johal, A., Imburgio, S., & Pannu, V. (2022). A rare and unusual cause of ischemic stroke to be aware of. Journal of Medical Cases, 13(11), 536–540. https://doi.org/10.14740/jmc4015
Kahraman, A. S., Kahraman, B., & Ozdemir, Z. M. (2016). Congenital agenesis of right internal carotid artery: A report of two cases. Journal of the Belgian Society of Radiology, 100(1), 48. https://doi.org/10.5334/jbr-btr.1015
Markovic, I., Milenkovic, Z., & Jocic-Jakubi, B. (2022). Stroke in sickle cell disease in association with bilateral absence of the internal carotid arteries: Case report. BMC Neurology, 22(1), 182. https://doi.org/10.1186/s12883-022-02702-5
Hebant, B., Gerardin, E., & Delpierre, C. (2020). A case of right internal carotid agenesis with associated transcavernous anastomosis revealed by transient ischemic attack. Surgical and Radiologic Anatomy, 42(2), 207–210. https://doi.org/10.1007/s00276-019-02318-4
Kiritsi, O., Noussios, G., & Tsitas, K. (2012). Unilateral agenesis of the internal carotid artery presented as transient ischaemic attack: A case report. Surgical and Radiologic Anatomy, 34(5), 475–477. https://doi.org/10.1007/s00276-011-0901-z
Liau, Y. J., Jabbour, A. J., & Yerdon, H. (2023). Bilateral internal carotid artery agenesis in a patient with a family history of intracranial pathology. Ochsner Journal, 23(1), 88–91. https://doi.org/10.31486/toj.22.0052
Jianu, D. C., Bârsan, C., & Dan, T. F. (2018). Left internal carotid artery agenesis associated with communicating arteries anomalies: A case report. Romanian Journal of Morphology and Embryology, 59(2), 601–605.
Saal-Zapata, G., & Rodriguez-Calienes, A. (2022). Agenesis of the internal carotid artery associated with intracranial aneurysms: Endovascular treatment and intraoperative complications management. Neuroradiology Journal, 35(6), 768–771. https://doi.org/10.1177/19714009221096833
Vasović, L., & Mrkaić, A. (2022). Congenital unilateral absence of the internal carotid artery associated with aneurysms of different arteries: A review. World Neurosurgery, 164, 393–412. https://doi.org/10.1016/j.wneu.2022.05.141
Yousaf, A., Yasin, A. L. F., & Homssi, M. (2023). Unilateral developmental absence of internal carotid artery with contralateral middle cerebral artery occlusion. Surgical and Radiologic Anatomy, 45(3), 327–332.
https://doi.org/10.1007/s00276-022-03056-w
AlAni, A. M., Al-Ekeer, A. N., & Kolleri, J. J. (2022). Left common carotid artery agenesis with independent origins of the external and internal carotid arteries from the aortic arch: A rare case in a patient with ankylosing spondylitis. Cureus, 14(8), e28456. https://doi.org/10.7759/cureus.28456
Views:
8
Downloads:
4
Copyright (c) 2025 Hubert Stachowicz, Karolina Paterek, Aleksandra Makarewicz, Aleksandra Pacek, Joanna Mazurek, Wojciech Gąska, Maciej Samczuk

This work is licensed under a Creative Commons Attribution 4.0 International License.
All articles are published in open-access and licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0). Hence, authors retain copyright to the content of the articles.
CC BY 4.0 License allows content to be copied, adapted, displayed, distributed, re-published or otherwise re-used for any purpose including for adaptation and commercial use provided the content is attributed.