Eur J Cardiothorac Surg 2008;33:1155-1156. doi:10.1016/j.ejcts.2008.03.001
Copyright © 2008, European Association for Cardio-thoracic Surgery. Published by Elsevier. All rights reserved.
Thymoma appearing 10 years after an extended thymectomy for myasthenia gravis
Alper Tokera,*,
Serhan Tanjua,
Yasemin Ozlukb,
Piraye Serdarogluc
a Istanbul University, Istanbul Medical Faculty, Department of Thoracic Surgery, Istanbul, Turkey
b Istanbul University, Istanbul Medical Faculty, Department of Pathology, Istanbul, Turkey
c Istanbul University, Istanbul Medical Faculty, Department of Neurology, Istanbul, Turkey
Received 13 December 2007;
received in revised form 11 February 2008;
accepted 4 March 2008.
* Corresponding author. Address: Inonu Cad, Yildiz Sok. STFA Bloklari, B/6 Blok No: 13, 81090 Kozyatagi, Kadikoy, Istanbul, Turkey. (Email: aetoker{at}superonline.com).
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Abstract
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Occurrence of thymoma after an extended thymectomy through a full median sternotomy for nonthymomatous thymectomy has been very rarely reported. A 60-year-old male patient who had myasthenia gravis (MG) for 11 years had an extended thymectomy operation with a pathology of thymic hyperplasia and developed a mass in the aortopulmonary window. We resected the mass via anterior left thoracotomy by dividing the ductus arteriosus and mobilizing the aorta. Cord vocal augmentation procedure was done due to the resection of the left recurrent laryngeal nerve.
Key Words: Thymoma • Extended thymectomy • Myasthenia gravis
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1. Introduction
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The general consensus in performing thymectomy in adults with MG is to induce remission or improvement, or permit a reduction in immunosuppressive medication [1]. Extended thymectomy includes the resection of all mediastinal fatty tissue with resection of both mediastinal pleuras through a full median sternotomy or with VATS technique via sternal lifting [2,3].
Occurrence of thymoma after nonthymomatous thymectomy has very rarely been reported [4,5]. Here, we present a patient who developed a thymoma 10 years after an extended thymectomy procedure through a total median sternotomy.
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2. Case report
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A 60-year-old male patient was admitted to our department because of the presence of a mass in the aortopulmonary window in his chest computerized tomographies (CT) (Fig. 1
). He had myasthenia gravis for 11 years. He had an extended thymectomy operation through a total median sternotomy which defined a pathology of thymic hyperplasia 10 years ago in one of the major chest surgery centers for thymic operations. During his examinations an increasing need for anticholinesterase and immunosuppressive medications for MG made the neurologists perform a repeat chest CT. It revealed a mass in the aortopulmonary window. His physical examination was normal; his blood chemistry and tumor markers, such as alphafetoprotein and beta HCG, were found to be in normal ranges. His antiacetylcholine receptor antibody level was above the range before the first operation. He did not have follow-ups, but his antiacetylcholine receptor antibody level was high again before the second operation. He was scheduled for an exploratory diagnostic VATS operation to exclude the possibilities of lung cancer or a lymphoma under 180 mg/day pyridostigmine bromide and 100 mg/day Azathioprine. Through a left sided VATS procedure we diagnosed a mass located at the aortopulmonary window with its intrapericardial extension. Frozen section analyses demonstrated an epithelial tumor-like thymoma. An anterior left thoracotomy was performed. After opening the intrapericardial space and dissection under the adventitia of pulmonary artery and aorta, by dividing the ductus arteriosus and ligating–dividing intercostal vessels, we mobilized the aorta and we resected the mass completely Fig. 2A). But during this manuever it was impossible to spare the left recurrent laryngeal nerve. Pericardial defect was reconstructed with PTFE graft. He had a cord vocal augmentation procedure postoperatively due to the resection of recurrent laryngeal nerve. He had a full dose of postoperative radiotherapy due to invasion of the thymoma to adventitia of the pulmonary artery and aorta. His chest CT controls demonstrated the extension of the operative procedure and was free of local recurrence (Fig. 2B).
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Fig. 2. (A) Polygonal tumor cells with ground-glass nuclei. Note the low number of lymphocytes (HE x400). (B) Postoperative chest CT. Metallic clips could be seen in the left paratracheal space and in the medial face of arcus aorta.
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3. Discussion
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The aim of this presentation is to stress the development of thymoma after one of the major thymectomy procedures of extended thymectomy via complete sternotomy. As the resection area of an extended thymectomy includes the aortopulmonary window, presence of a thymoma in this location raises the following questions:- (1) Was there a neoplastic thymic cell within the first specimen, which stayed as a residue?
- (2) Did a normal residual thymic cell develop into thymoma?
- (3) Did an ectopic thymic cell in the fatty compartment develop into a tumor?
Therefore, in this patient all possibilities converge on the quality of the extended thymectomy operation, which is impossible to evaluate due to the loss of specimen after 10 years. The above-mentioned possibilities could be true only if the previous procedure was a simple thymectomy, which does not propagate the dissection of aortopulmonary window. However, the previous operation was through a total median sternotomy and was claimed to be an extended thymectomy, which leaves the extra anatomic localization of thymoma as the main possibility [6]. Likewise, this also calls for the consideration of whether a maximal thymectomy according to Jaretzki could prevent the occurrence of thymoma after a nonthymomatous thymectomy [7].
We conclude that careful follow-up and performing CT at regular intervals is mandatory even years after a thymectomy procedure for myasthenia gravis.
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References
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Abstract
1. Introduction
