We detail what we believe to be the ﬁrst reported case of a congenital ‘Cervical Left Pulmonary Artery’ in which an aberrant left pulmonary artery courses cranially into the mid-cervical neck before descending back into the thorax to the left pulmon- ary hilum. Due to the location and course of the artery, we believe that this anomaly is likely due to a developmental error of the sixth pharyngeal arch. Ultimately, the use of a reconstructed 3D computed tomography image provided detailed char- acterization of the unique anatomical variant, aiding in a successful surgical repair of the defect. INTRODUCTION CASE REPORT Defects of the aortic arches are rare, potentially lethal cardiac Our patient is baby boy born at 35 weeks gestation with con- anomalies that form beginning in the third week of development genital lobar emphysema, VSD, double outlet right ventricle . There are numerous cardiac vascular anomalies attributed with the aorta to the right of the pulmonary artery in a side by to abnormal aortic arch development, including the double aor- side relationship. A CT scan performed on Day 11 showed a tic arch, right aortic arch, aberrant left or right subclavian artery, LPA originating from the posterior aspect of the right pulmon- anomalous innominate artery or pulmonary artery sling (PAS) ary artery (RPA). 3D computed tomography (3D-CT) reconstruc- . Amongst the larger class, anomalies of the left pulmonary tion showed the LPA coursing superiorly into the mid-cervical artery (LPA) are particularly rare, with the PAS being the most neck before descending into the left thorax to the left pulmon- common. ary hilum (Fig. 1). The anomalous LPA remained anterior to the While mild cases may appear asymptomatic, the majority of cervical trachea, and there was evidence of left upper lobe neonates with aortic arch abnormalities present with respiratory bronchial stenosis. The CT scan also illustrated a double outlet or upper gastrointestinal symptoms as a result of compression of right ventricle, a moderate sized ventricular septal defect, con- the trachea and/or esophagus . The use of echocardiography, genital lobar emphysema, abnormal development of the thy- computed tomographic angiography, magnetic resonance angiog- roid and increased collateral circulation of the pulmonary raphy and barium contrast esophagogram can be crucial for diag- arterial system with aortopulmonary collaterals. nosis when a vascular etiology for respiratory or upper digestive A left thoracotomy upper left lobe lobectomy and medias- symptoms is suspected . tinal cyst removal was performed at 5 weeks of age. Over the Received: September 14, 2017. Accepted: November 29, 2017 Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author(s) 2018. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact firstname.lastname@example.org Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx252/4822186 by Ed 'DeepDyve' Gillespie user on 16 March 2018 2 M.Q. Schmidt et al. Figure 1: Pre-operative 3D-CT reconstruction showing the left pulmonary artery Figure 2: Post-operative 3D-CT reconstruction showing the repaired left pul- ascending into the neck. monary artery. next 3 weeks the patient required increased oxygen require- the sixth pharyngeal arch and forms the pulmonary arteries ments and repair of his many cardiac defects was recom- between the fourth and eighth weeks of development. Other mended. At 8 weeks of age the patient underwent a LPA plasty anatomic structures derived from sixth pharyngeal arch meso- with supramitral ring resection, RV bundle resections and derm include the majority of the intrinsic laryngeal muscles enlargement of the VSD. The LPA plasty created a spatulated and laryngeal cartilage. The recurrent laryngeal nerve (RLN) anastomosis between the proximal ascending LPA and the dis- innervates the laryngeal musculature within the sixth pharyn- tal descending LPA. A post-surgical CT scan showed successful geal arch, and as the cardiac and aortic structures migrate into repositioning of the LPA (Fig. 2). There was a new, post- the thoracic region, the RLN lengthens along this migratory operative right ventricular outﬂow tract aneurysm near the tract. In the current case, the patient’s LPA ascends to the level junction of the LPA, as well as the persistence of a small VSD. of the larynx, the ﬁnal location of sixth pharyngeal arch struc- Post-operatively, the patient was discharged after adequate tures. After arching, the ‘descending limb’ of the LPA re-enters recovery. The patient had recurrent respiratory tract infections the thorax in close proximity to the anatomical tract of the left requiring multiple hospitalizations. Additionally, further echo- RLN within the left tracheoesophageal groove, the migratory cardiograms during these hospitalizations displayed continued tract of sixth arch structures. Due to these striking relation- cardiac defects that required further repair at 6 months of age. ships, we hypothesize that the cervical LPA is related to a developmental defect in which the LPA failed to fully separate from the other structures of the sixth pharyngeal arch. DISCUSSION There are other less likely mechanisms that warrant consid- To our knowledge, this is the ﬁrst reported case reported of a eration. As previously noted, the most common LPA abnormal- congenital LPA that extends into the neck. With early signs of ity seen is the PAS, in which the LPA originates from the bronchial stenosis, it is likely that the patient would have posterior aspect of the RPA, encircles the right mainstem bron- developed severe complications, similar to those seen in other chus, and then passes between the esophagus and trachea as it congenital vascular abnormalities. For example, infants with courses to the left lung . Since our patient’s LPA had a similar severe tracheal stenosis due to PAS are reported to have mor- origin from the posterior RPA, the two main hypotheses by Jue tality rates as high as 90% without surgical correction . Thus, et al. and Sade et al. [5, 6], which explain the formation of PAS effective surgical repair is of upmost importance in these cases. should be considered. These papers theorize that failure of Multiple aspects of this case suggest that the etiology is standard LPA development creates the need for an alternative related to a defect in aortic arch development. In normal devel- source of blood supply for the left lung; thus, a fairly direct con- opment, the sixth aortic arch derives from the mesoderm of nection forms between the RPA and left lung hilum, which is Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx252/4822186 by Ed 'DeepDyve' Gillespie user on 16 March 2018 Cervical left pulmonary artery 3 the resulting aberrant LPA. In the current case, it is unlikely REFERENCES that the anomaly was driven by a need for collateral ﬂow due 1. Hanneman K, Newman B, Chan F. Congenital variants and to the dramatic, indirect course of the LPA into the mid-cervical anomalies of the aortic arch. Radiographics 2017;37:32–51. neck. Additionally, in all reported cases of the PAS, the LPA 2. Valletta EA, Pregarz M, Bergamo-Andreis IA, Boner AL. passes between the trachea and esophagus; in this case, the Tracheoesophageal compression due to congenital vascular arch of the cervical LPA remains anterior to the trachea, further anomalies (vascular rings). Pediatr Pulmonol 1997;24:93–105. differentiating this from the standard PAS and suggesting a 3. Shah RK, Mora BN, Bacha E, Sena LM, Buonomo C, Del Nido unique etiology. P, et al. The presentation and management of vascular rings: Finally, the use of 3D-CT reconstruction modeling was para- an otolaryngology perspective. Int J Pediatr Otorhinolaryngol mount in detailing the unique and complex anatomy of this 2007;71:57–62. infant boy. There are concerns regarding the high levels of radi- 4. Collins RT 2nd, Weinberg PM, Ewing S, Fogel M. Images in ation exposure from CT in pediatric patients, so this modality cardiovascular medicine. Pulmonary artery sling in an should be used sparingly. However, in cases with unique aortic asymptomatic 15-year-old boy . Circulation 2008;117:2403–6. vasculature, a detailed anatomic description is paramount 5. Jue KL, Raghib G, Amplatz K, Adams P Jr., Edwards JE. before undertaking interventional or vascular procedures . In Anomalous origin of the left pulmonary artery from the right this case, the model developed from 3D-CT reconstruction was pulmonary artery. Report of 2 cases and review of the litera- useful for pre-operative and intra-operative planning, aiding ture. Am J Roentgenol Radium Ther Nucl Med 1965;95:598–610. our surgeons in performing a successful repair of the anomaly. 6. Sade RM, Rosenthal A, Fellows K, Castaneda AR. Pulmonary artery sling. J Thorac Cardiovasc Surg 1975;69:333–46. 7. Jakanani GC, Adair W. Frequency of variations in aortic arch CONFLICT OF INTEREST STATEMENT anatomy depicted on multidetector CT. Clin Radiol 2010;65: None declared. 481–7. Downloaded from https://academic.oup.com/jscr/article-abstract/2018/1/rjx252/4822186 by Ed 'DeepDyve' Gillespie user on 16 March 2018
Journal of Surgical Case Reports – Oxford University Press
Published: Jan 1, 2018
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