Ann Thorac Surg 2002;73:985-986
© 2002 The Society of Thoracic Surgeons
Case report
Right aortic arch with left lung cancer: focusing on left recurrent laryngeal nerve
Dai Shida, MD*a,b,
Yuji Asato, MDa,b,
Ryuta Amemiya, MDa,b,
Akifumi Suzuki, MDa,b,
Fuyo Yoshimi, MDa,b
a Department of Surgery, Ibaraki Prefectural Central Hospital Ibaraki, Japan
b Cancer Center, Ibaraki, Japan
Accepted for publication June 13, 2001.
* Address reprint requests to Dr Shida, Department of Surgical Oncology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
e-mail: shida-dis{at}h.u-tokyo.ac.jp
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Abstract
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We report a case of a 64-year-old Japanese man with an anomalous right aortic arch who had left lung cancer. We performed lobectomy and mediastinal lymphadenectomy, paying attention to the pathway of left recurrent laryngeal nerve. The left recurrent laryngeal nerve hooked around from the left dorsal to the right ventral part of the left ductus arteriosus, which connected the left pulmonary artery with the aortic diverticulum.
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Introduction
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The incidence of left lung cancer with a right aortic arch is rare. During lobectomy and mediastinal lymphadenectomy, we need to pay particular attention not only to vascular abnormalities but also to the pathways of the vagus nerve and recurrent laryngeal nerve. The following is a case of a 64-year-old Japanese man with right aortic arch who had left lung cancer. The right aortic arch had an aberrant left subclavian artery that was classified as IIIB type according to the classification of Stewart and colleagues [1]. The left ductus arteriosus connected the left pulmonary artery with the aortic diverticulum of the left subclavian artery and the left recurrent laryngeal nerve encircled it from the left dorsal to the right ventral.
A 64-year-old man was admitted to our hospital in June 1999 for an investigation of an abnormal shadow on a medical checkup chest roentgenogram. A lateral view on admission showed one shadow measuring 2.5 cm that coincided with eighth thoracic vertebrae. In a posteroanterior view, the aortic knob could be identified to the right of the trachea and slightly more cranial than the usual position of the left aortic knob. The shadow usually produced by a normal aortic arch to the left of the trachea was absent, therefore we supposed that the patient had an right aortic arch. A computed tomographic scan of the shadow subsequently revealed a nodule measuring 2.5 cm in the left lower lobe (S6), which had spicular radiation and pleural indentation. Transbronchial aspiration cytology was performed at that point and the specimens yielded a diagnosis of adenocarcinoma. Pulmonary arteriography showed no abnormalities and a cardiac evaluation including an echocardiogram revealed no congenital heart anomaly. Three-dimensional reconstructed image of magnetic resonance angiography revealed the left subclavian artery entering a small round pouch, which was the so-called aortic diverticulum, to the left of the right descending aorta (Fig 1).
Thus, a diagnosis of HIB type right aortic arch, with left lung cancer was made. The cTNM classification was defined as T1 N0 M0.
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Fig 1. Three-dimensional reconstructed image of magnetic resonance angiography showing the right aortic arch with an aberrant left subclavian artery. The left common carotid artery (LCCA) arose as the first branch of the right aortic arch and was followed by the right common carotid (RCCA) and right subclavian (RSA) arteries. The last branch of the arch was the left subclavian artery (LSA), which connected to the descending aorta through the so-called aortic diverticulum (AD). (LPA = left pulmonary artery.)
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A left lower lobectomy and mediastinal lymphadenectomy were performed through a left thoracotomy on July 17, 1999, and the pathologic staging was stage IB (T2 N0 M0). Mediastinal lymphadenectomy was done easily because the aortic arch was positioned on the other side. The left ductus arteriosus arose from the left pulmonary artery, passed in an upper posterior direction, and terminated on the aortic diverticulum (Fig 2).
And, for lymphadenectomy, we divided the left ductus arteriosus, which had no lumen and was found to be closed. The left recurrent laryngeal nerve approached the back of the left ductus arteriosus, encircled it from the left dorsal to the right ventral, and went upward along the left surface of the esophagus and trachea.
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Fig 2. Drawing of the left recurrent laryngeal nerve (LRLN) showing the relationship with the vascular structures and left ductus arteriosus in the present case. The left ductus arteriosus (LDA) connected the left pulmonary artery (LPA) with the aortic diverticulum of the left subclavian artery (LSA). The left recurrent laryngeal nerve hooked around from the left dorsal to the right ventral part of the left ductus arteriosus. (LCCA = left common carotid artery.)
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Comment
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Right aortic arch is a congenital anomaly where the heart is in its normal position and the aorta arches to the right and backward over the right bronchus, contrary to normal. This anomaly occurs in approximately 0.1% to 0.14% of the population [2].
The classification of aortic arch anomalies by Stewart and colleagues [1] is well-known. Group III right aortic arch is classified into three major groups and our patient was classified as IIIB type. Concerning the connection between congenital heart disease with the right aortic arch, Stewart and associates [3] mentioned that, among IIIA type, 98% had congenital heart disease such as tetralogy of Fallot, and that, among IIIB type, only 12% had congenital heart disease. Type IIIB is ordinarily not associated with congenital heart disease and usually goes unnoticed until middle age. It is often found incidentally, as was the case with our patient.
During this operation, we needed to pay particular attention not only to vascular abnormalities but also to the pathways of the vagus nerve and recurrent laryngeal nerve. The IIIB type right aortic arch usually has the left ductus arteriosus connecting the left pulmonary artery with the aortic diverticulum of the left subclavian artery. And in such cases, according to past reports, it seems that the left recurrent laryngeal nerve usually encircles the left ductus arteriosus [4, 5]. This time, by preoperative computed tomographic scan and magnetic resonance angiography, we diagnosed that the right aortic arch had an aberrant left subclavian artery, therefore we could anticipate the location of the left ductus arteriosus and left recurrent laryngeal nerve preoperatively. As a result, we could perform the operation safely and smoothly.
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References
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Stewart J.R., Kincaid O.W., Edwards J.E. Malformations with right aortic arch (Group III). In: Stewart J.R., Kincaid O.W., Edwards J.E., eds. An atlas of vascular rings and related malformations of the aortic arch system. Springfield: Charles C Thomas, 1964:80-129.
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Hastreiter A.R., D’Cruz I.A., Cantez T. Right-sided aorta. Part I: Occurrence of right aortic arch in various types of congenital heart disease. Br Heart J 1966;28:722-725.[Free Full Text]
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Stewart J.R., Kincaid O.W., Titus J.L. Right aortic arch: plain film diagnosis and significance. Am J Roentgenol 1966;97:377-389.[Free Full Text]
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Serisawa M., Shigehara N., Takahashi H., Eto M. Gross anatomical observations on two cases of right-sided arch of the aorta with the left subclavian artery as its last branch. Okajimas Folia Anat Jpn 1992;68:377-392.[Medline]
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Shibata M., Shimada K., Goto N. Case report of the right-sided aortic arch (N-type): New classification based on macroscopic observations. Kaibougaku Zassi (Acta anat Nippon) 1998;73:163-170.
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Abstract
Introduction
