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Retrotracheal mediastinal goiter with contralateral extension
CORRESPONDENCE
Retrotracheal Mediastinal Goiter With Contralateral Extension To the Editor: I was interested in reading the case report written by Van Schil and associates [l]. No detail is given about the former cervical operation; it can be supposed it was performed on the left lobe. This occurrence would illustrate one of the traps of cervicothoracic surgery: the undiscovered plunge of a cervical goiter, when its “waistline” at the cervicothoracic opening is so thin it can be mistaken for a thick inferior thyroid pedicle and when its thoracic part i s still small. As for the ”crossing over” plunge, it happens more often from left to right because of anatomical vascular reasons and it may be anterior to the veins, in the thymic lodge, or posterior. This contralateral development can be suspected on a standard frontal chest roentgenogram: the tracheal clarity is lateral, but on the side where the cervical thyroid lobe is apparently enlarged (it would be on the right side in this case). Van Schil and associates do not mention this point and they do not give the time elapsed between the two operations. It is remarkable that computed tomographic scans showed a substernal extension, as the thymic lodge looks quite empty on the lateral chest roentgenogram. The fibrous bands found at operation, secondary to the first operation, probably barred the goiter from the more natural and frequently used anterior way down the mediastinum. I personally think that two plain chest roentgenograms and an esophagram give sufficient information on a posterior mediastinal goiter. Frontal and lateral magnetic resonance imaging might be of interest. Thyroid scanning is negative in 45% of cases in my experience. I agree with Van Schil and associates that sternotomy is better than blind operation in such a case. Posterolateral thoracotomy has also been used for a fixed, left behind, or undiagnosed thyroid mass. It can be misleading and it is generally very important to define the exact topography of any goiter before operation: it may happen that the larger cervical lobe does not plunge, while the contralateral, apparently normal lobe does, and that resection is therefore performed on the wrong lobe! Between 10% and 15% of patients with mediastinal goiters had a cervical thyroidectomy in the past and the mean delay between the two operations is more than 10 years. Usually symptoms of compression arise. Good chest roentgenograms and complete exploration of the two lobes are obligatory in cervical thyroid operations. Posterior mediastinal goiters may have several extensions, dissociating trachea and esophagus. I never saw a posterior goiter crossing the mediastinum from the right; there is enough space on that side. But all forms can be observed (such as associated anterior and posterior extensions), and that is another argument against blind operation. Apart from plain frontal and lateral chest roentgenograms and esophagram, magnetic resonance imaging looks to me more promising than computed tomographic scans because of the possibility of frontal and lateral incidences; there are many traps in cervicomediastinal thyroid operations [2].
Fig I. Anteroposterior chest roentgenogram showing right paratracheal mediastinal mass (arrows). The tracheal clarity (arrowheads) is not displaced. References 1. Van Schil P, Vaneerdeweg W, Schoofs E, Abs R. Retrotracheal mediastinal goiter with contralateral extension [Letter]. Ann Thorac Surg 1989;48:889-90. 2. Ribet M. Chirurgie thoracique generale. Paris: Masson Publishers, 1989:215-8.
Reply
To the Editor:
I thank Dr Ribet for his very interesting remarks about mediastinal goiters. As the original report had to be shortened some details were omitted. The time interval between the two thyroid operations in our patient was 27 years. The first operation was performed at another hospital and no exact operative or pathological details were available. Presumably she underwent a bilateral subtotal thyroidectomy for a multinodular goiter. On the standard frontal chest roentgenogram the tracheal clarity was not displaced laterally (Fig 1).On the lateral view the trachea was displaced ventrally by the posteriorally located mass but, of course, this did not give any information about contralatera1 extension. Computed tomographic and technetium thyroid scanning were not very helpful either in demonstrating the crossing over. Magnetic resonance imaging was not performed in our patient but looks very promising. Considering the operative approach, a right lateral thoracotomy in this secondary goiter would not have offered any advantage as the right mediastinal thyroid came from the left side. A lateral thoracotomy may, however, be indicated in case of a primary intrathoracic goiter as blood supply entirely comes from local mediastinal vessels.
M . Ribet, M D
P. Van Schil, M D
Thoracic Surgery H6pital Calmette CHU F . 59037 Lille CMex France
Department of Surgery University Hospital of Antwerp Wilrijkstraat 10 8-2520 Edegem Belgium
0 1990 by The Society of Thoracic Surgeons
Ann Thorac Surg 1990;50:6848
0003-4975/90/$3.50
Retrotracheal Mediastinal Goiter With Contralateral Extension To the Editor: I was interested in reading the case report written by Van Schil and associates [l]. No detail is given about the former cervical operation; it can be supposed it was performed on the left lobe. This occurrence would illustrate one of the traps of cervicothoracic surgery: the undiscovered plunge of a cervical goiter, when its “waistline” at the cervicothoracic opening is so thin it can be mistaken for a thick inferior thyroid pedicle and when its thoracic part i s still small. As for the ”crossing over” plunge, it happens more often from left to right because of anatomical vascular reasons and it may be anterior to the veins, in the thymic lodge, or posterior. This contralateral development can be suspected on a standard frontal chest roentgenogram: the tracheal clarity is lateral, but on the side where the cervical thyroid lobe is apparently enlarged (it would be on the right side in this case). Van Schil and associates do not mention this point and they do not give the time elapsed between the two operations. It is remarkable that computed tomographic scans showed a substernal extension, as the thymic lodge looks quite empty on the lateral chest roentgenogram. The fibrous bands found at operation, secondary to the first operation, probably barred the goiter from the more natural and frequently used anterior way down the mediastinum. I personally think that two plain chest roentgenograms and an esophagram give sufficient information on a posterior mediastinal goiter. Frontal and lateral magnetic resonance imaging might be of interest. Thyroid scanning is negative in 45% of cases in my experience. I agree with Van Schil and associates that sternotomy is better than blind operation in such a case. Posterolateral thoracotomy has also been used for a fixed, left behind, or undiagnosed thyroid mass. It can be misleading and it is generally very important to define the exact topography of any goiter before operation: it may happen that the larger cervical lobe does not plunge, while the contralateral, apparently normal lobe does, and that resection is therefore performed on the wrong lobe! Between 10% and 15% of patients with mediastinal goiters had a cervical thyroidectomy in the past and the mean delay between the two operations is more than 10 years. Usually symptoms of compression arise. Good chest roentgenograms and complete exploration of the two lobes are obligatory in cervical thyroid operations. Posterior mediastinal goiters may have several extensions, dissociating trachea and esophagus. I never saw a posterior goiter crossing the mediastinum from the right; there is enough space on that side. But all forms can be observed (such as associated anterior and posterior extensions), and that is another argument against blind operation. Apart from plain frontal and lateral chest roentgenograms and esophagram, magnetic resonance imaging looks to me more promising than computed tomographic scans because of the possibility of frontal and lateral incidences; there are many traps in cervicomediastinal thyroid operations [2].
Fig I. Anteroposterior chest roentgenogram showing right paratracheal mediastinal mass (arrows). The tracheal clarity (arrowheads) is not displaced. References 1. Van Schil P, Vaneerdeweg W, Schoofs E, Abs R. Retrotracheal mediastinal goiter with contralateral extension [Letter]. Ann Thorac Surg 1989;48:889-90. 2. Ribet M. Chirurgie thoracique generale. Paris: Masson Publishers, 1989:215-8.
Reply
To the Editor:
I thank Dr Ribet for his very interesting remarks about mediastinal goiters. As the original report had to be shortened some details were omitted. The time interval between the two thyroid operations in our patient was 27 years. The first operation was performed at another hospital and no exact operative or pathological details were available. Presumably she underwent a bilateral subtotal thyroidectomy for a multinodular goiter. On the standard frontal chest roentgenogram the tracheal clarity was not displaced laterally (Fig 1).On the lateral view the trachea was displaced ventrally by the posteriorally located mass but, of course, this did not give any information about contralatera1 extension. Computed tomographic and technetium thyroid scanning were not very helpful either in demonstrating the crossing over. Magnetic resonance imaging was not performed in our patient but looks very promising. Considering the operative approach, a right lateral thoracotomy in this secondary goiter would not have offered any advantage as the right mediastinal thyroid came from the left side. A lateral thoracotomy may, however, be indicated in case of a primary intrathoracic goiter as blood supply entirely comes from local mediastinal vessels.
M . Ribet, M D
P. Van Schil, M D
Thoracic Surgery H6pital Calmette CHU F . 59037 Lille CMex France
Department of Surgery University Hospital of Antwerp Wilrijkstraat 10 8-2520 Edegem Belgium
0 1990 by The Society of Thoracic Surgeons
Ann Thorac Surg 1990;50:6848
0003-4975/90/$3.50