Ann Thorac Surg 2008;85:1427-1429. doi:10.1016/j.athoracsur.2007.10.075
© 2008 The Society of Thoracic Surgeons
Case Reports
Radical Excision of Thymic Adenocarcinoma with Selective Cerebral Perfusion
Masakazu Yoshioka, MDa,*,
Osamu Ichiguchi, MDa,
Touitsu Hirayama, MDb,
Toshiharu Sassa, MDb,
Takihiro Kamio, MDc
a Department of Thoracic Surgery, Saiseikai Kumamoto Hospital, Kumamoto, Japan
b Department of Cardiovascular Surgery, Saiseikai Kumamoto Hospital, Kumamoto, Japan
c Department of Pathology, Saiseikai Kumamoto Hospital, Kumamoto, Japan
Accepted for publication October 23, 2007.
* Address correspondence to Dr Yoshioka, Department of Thoracic Surgery, Saiseikai Kumamoto Hospital, Chikami 5-3-1, Kumamoto, 861-4193, Japan (Email: masakazu-yoshioka{at}saiseikaikumamoto.jp).
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Abstract
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Most cases of thymic carcinoma have some invasion to neighboring organs when diagnosed, and it is generally difficult to completely remove. We adopted selective cerebral perfusion as a cerebral protection and successfully performed resection of a thymic adenocarcinoma that involved the superior vena cava, left brachiocephalic vein, right brachiocephalic artery and vein, and left common carotid artery in a 47-year-old woman. Even if multiple great vessels were involved by mediastinal malignant tumor, complete resection with selective cerebral perfusion could be safely performed.
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Introduction
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In most cases of mediastinal malignant tumor, tumors often involve neighboring organs (ie, the great vessels, lungs, pericardium, nerves, or trachea) [1, 2]. Thymic carcinoma is believed to have a dismal prognosis as compared with that of thymoma because most of these tumors have some invasion to neighboring organs when diagnosed [3]. Although some invasion occurs, acceptable prognosis will be obtained by surgery if complete resection is carried out [1]. This is the first report of successful excision with selective cerebral perfusion of a thymic carcinoma that involved great vessels.
A 47-year-old woman was identified as having a mediastinal abnormal shadow in chest computed tomography in a health screening. She had been suffering from an abnormal sensation in her throat during swallowing for the past 3 months. She did not have concomitant myasthenia gravis. She was referred to our hospital for examination and treatment in November 2006. A contrast medium-enhanced computed tomographic scan showed an anterior upper mediastinal tumor with a diameter of approximately 7 x 5 cm that had invaded and involved the superior vena cava (SVC), right brachiocephalic artery and vein, left brachiocephalic vein, and left common carotid artery (LCCA) (Fig 1). The tumor was faintly enhanced by contrast medium. In the fluorodeoxyglucose positron emission tomography study, the tumor showed strong uptake of fluorodeoxyglucose, but there was no abnormal uptake in the other organ. Because of these invasive findings and its location, we suspected that the tumor might be a malignant thymic tumor (ie, invasive thymoma or thymic cancer). Video assisted-thoracoscopic surgery biopsy and pathologic examination revealed adenocarcinoma in December 2006. We diagnosed the tumor as thymic adenocarcinoma, and the clinical stage was defined as Masaoka stage III [4]. The operation was performed through a collar skin incision and median sternotomy in January 2007. We decided that the tumor could be removed by resection and grafting of these great vessels, because the tumor had not invaded the trachea. After systemic heparin administration (300 IU/kg), extracorporeal circulation was instituted with the arterial return cannula placed in the ascending aorta and a single two-stage cannula in the right atrium. Cardiopulmonary bypass was begun and the heart was arrested with cold blood cardioplegia. The patient was cooled to a rectal temperature of 20°C. First, the involved veins were removed. Because the left brachiocephalic vein was completely involved, the vein was ligated and transected at the left extremity of the tumor. Because more than 50% of the circumference of the left side of the SVC and the right brachiocephalic vein was involved, the proximal end of the SVC and the distal end of the right brachiocephalic vein were clamped, and approximately 80% of the circumference of the SVC and the right brachiocephalic vein was resected. Reconstruction of the SVC and right brachiocephalic vein was done using a glutaraldehyde-processed equine pericardial patch (Edwards Lifesciences LLC, Irvine, CA), and the clamp was then released. Next, the involved arteries were transected. The right subclavian artery, the root of the right brachiocephalic artery, the root of the LCCA, and the LCCA distal to the tumor-involved lesion was exposed. After clamping of the right subclavian artery, the root of the right brachiocephalic artery, and the LCCA, the right subclavian artery, the right common carotid artery, and the LCCA were transected distal to the invaded lesion. The cannulas for selected cerebral perfusion (SCP) were inserted into the right common carotid artery and the LCCA from inside the Y-graft (16 x 8 mm, InterGard Knitted [Intervascular, La Ciotat, France]), and the SCP was started. Each distal limb of the Y-graft and the stumps of the right common carotid artery and LCCA were connected by a running suture. Both the origin of the right brachiocephalic artery and the origin of the LCCA were cut together at the aortic arch. The tumor was thereby removed with the involved vessels. At this time, both the right recurrent laryngeal nerve and the right vagal nerve were sacrificed due to the involvement of the tumor. The anastomosis between the proximal end of the Y-graft and the stump of the aortic arch was performed end-to-side. After completion of the Y-graft anastomosis, antegrade systemic circulation was begun from the side limb of the Y-graft. Then, the anastomosis between the stump of the right subclavian artery and the side of the right limb of the Y-graft, which was connected to the right common carotid artery, was performed by graft interposition. After all anastomoses of the arteries were accomplished, SCP was discontinued, cardiopulmonary bypass was gradually returned to normal flow, and rewarming was begun. Reconstruction of the left brachiocephalic vein was carried out by a glutaraldehyde-processed equine pericardial patch roll interposition (Fig 2). After the insertion of three drains to the right pleural, pericardial, and retrosternal spaces, the sternum and skin were closed. The duration of the operation was 474 minutes, cardiopulmonary bypass time was 211 minutes, SCP time was 47 minutes, and SVC clamping time was 18 minutes. The total blood transfusion was 6 U. Histologically, the tumor was diagnosed as adenocarcinoma of the thymus (Fig 3). Tissue cutting for the whole resected specimen was performed, but other than the adenocarcinoma, neither thymoma nor teratoma was seen. It was confirmed pathologically that a complete resection had been achieved.
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Fig 1. Chest computed tomographic scan shows invasion of the right brachiocephalic artery, the left common carotid artery, and the superior vena cava.
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Postoperatively, the patient underwent anticoagulation therapy with oral warfarin sodium and aspirin. The length of stay in the intensive care unit was 3 days. She was discharged on postoperative day 21 and was readmitted 10 days later with mild face edema and dyspnea. Chest roentgenogram showed bilateral pleural effusion. Contrast medium-enhanced computed tomography showed good graft patency. After addition of the oral diuretics therapy, these symptoms, which had led us to suspect SVC syndrome, were immediately disappeared. At 4 months after surgery, a contrast medium-enhanced computed tomographic scan showed good graft patency, and the patient underwent systemic platinum-based chemotherapy.
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Comment
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Because thymic adenocarcinoma is a very rare histologic type in thymic tumors, reports regarding the clinical prognosis and treatment of choice for thymic adenocarcinoma have been scarcely provided [5]. Therefore, we have had to determine the treatment strategy for thymic adenocarcinoma through case reports about thymic carcinoma, most of which were squamous cell carcinoma [1, 6].
Local regional invasion of nearby organs by thymic carcinoma is very common. Tseng and colleagues [6] have reported that if the tumor invading the SVC could be en bloc resected, the patient could still achieve long-term survival. They suggested that complete resection of a tumor is a significant prognostic factor of survival rate. In almost all reports regarding resection of mediastinal tumors invading the great vessels, the invaded and resected vessels have been only great veins (ie, SVC or innominate veins, or both). Simultaneous resection and reconstruction of the great veins and arteries in the mediastinum for removal of a thymic tumor has not been reported yet. Fortunately, because the present case had no distant metastasis, acceptable prognosis was estimated based on whether the tumor was completely removed. Some groups suggested that preoperative chemotherapy seemed to increase survival of patients with invasive thymic tumors and should be strongly considered [6, 7]. However, we decided to give priority to an operation, because reported favorable outcome that had been obtained by neoadjuvant therapy was mainly in the thymoma [7]. Effectiveness of chemotherapy for thymic cancer is still controversial, so surgical extirpation remains the standard of choice. Moreover, neoadjuvant chemotherapy usually results in dense fibrosis involving the structures at the site of infiltration, and this could make the dissection more difficult [7]. For these reasons, en bloc resection was given priority in this thymic adenocarcinoma case. Although SCP was needed for complete resection in this case, this technique has been used for protection of the brain during operation of the aortic arch (ie, total arch replacement for acute type A aortic dissection [8]). For expert cardiovascular surgeons, such a technique for resection and grafting of intact vessels in a mediastinal tumor patient whose cardiac function is normal is safer than when used in a patient undergoing aortic dissection. Therefore, we decided to remove the tumor with the involved great vessels after no invasion to the trachea was confirmed.
Our results suggest that multiple involvements of the great vessels do not preclude complete resection of a thymic carcinoma with the aid of SCP. Aggressive surgical management of a locally invasive thymic carcinoma is feasible and safe, even if a tumor has multiple great vessel invasions.
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References
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Abstract
Introduction
