A 45-year-old male was diagnosed with an anterior mediastinal tumor and referred to our hospital. Open biopsy results of the tumor revealed a squamous cell carcinoma and cytology findings were positive for pericardial effusion. Chest computed tomography (CT) showed a mass approximately 10 cm in size with invasion to the left hilar part of the left lung and aortic arch, as well as pericardial effusion (Fig. 1A-C), thus the patient was diagnosed with a thymic carcinoma, c-Stage IVa (cT4N0M1a). Six courses of chemotherapy with carboplatin and paclitaxel were performed, followed by tegafur/gimeracil/oteracil (S-1) administration for 1 year. Chest CT findings showed disappearance of pericardial effusion and slightly decreased tumor size (Fig. 1D-F), while fluorodeoxyglucose (FDG)-position emission tomography also revealed that FDG uptake was decreased after the chemotherapy regimen (Fig. 2). However, at this time the patient was affected by liver dysfunction due to chemotherapy, thus our multidisciplinary team considered surgical options because that administration could not be continued.
Preoperative systemic restaging was yc-Stage IIIb (yc-T4N0M0). A salvage operation including aortic arch replacement was considered to be challenging, thus we carefully explained the risk of surgery to the patient and his family, and obtained informed consent. A left lateral thoracotomy was initially performed, and the findings ruled out pleural or pericardial dissemination, thus a median sternotomy was added. Invasion of the chest wall by the tumor was noted, thus resection of the chest wall 8 x 5 in size as well as the pectoralis major muscle was performed. The tumor was suspected to have invaded the main pulmonary artery (PA) trunk as well as the aortic arch. The left brachiocephalic vein showed obvious tumor invasion and was dissected, though the mass could not be divided from the aorta. Moreover, the left PA could not be encircled in the pericardium. Following systemic heparinization (300 U/kg), a cardiopulmonary bypass (CPB) was established with right atrium drainage, as well as 2 points of arterial perfusion via the femoral and right axillary arteries. The shrunken left main trunk of the PA was then dissected and divided with a stapler, and the upper and lower pulmonary veins, and left main bronchus were also divided. Finally, the tumor was sharply separated from the aorta and removed along with the left lung. The left recurrent laryngeal and phrenic nerve were involved in the tumor and resected, whereas the cutting edge was negative for viable tumor cells in the pericardium and pulmonary artery, as shown by frozen section findings. Some tumor residue remained on the aortic wall and was confirmed to be viable, thus a residual tumor resection with replacement of the aortic arch using total rerouting of the supra-arch vessels (3) was performed. To confirm that no tumor remained other than in the aortic wall, selected points such as fat near the pulmonary artery and the aorta in the remaining area were confirmed to be negative by frozen section findings. Anastomoses of the ascending aorta and trunk of the trifurcation graft (Hemashield three-branch graft, 12-8-8 mm) were performed with side-clamping, and subsequently the brachiocephalic artery, left common carotid artery, and left subclavian artery were reconstructed one by one using a simple clamping method. Next, after clamping the ascending aorta just distal to the trifurcated graft inflow anastomosis and proximal descending aorta, the aortic arch was resected with the residual tumor and reconstructed using a 26-mm graft. Cardiac arrest was not introduced at any time during the procedure, though CPB could not be weaned because of right heart failure caused by PA bifurcation stenosis. Therefore, we reconstructed the PA bifurcation, the stenosis of which was due to the division line of the left PA being too close to the PA trunk, using an 18-mm tube graft (Fig. 3) for replacing the PA trunk and right PA. After PA repair, CPB was weaned uneventfully. For repair of the defect in the chest wall, a polypropylene mesh was fixed to the chest wall when the chest was closed. The operation time was 958 minutes and CPB time was 254 minutes, while blood loss was 7980 ml. The patient was extubated on postoperative day (POD) 2 and the postoperative course was uneventful. Pathological diagnosis results revealed that viable tumor cells were present in the resected aortic wall, indicating that the final pathological stage was IIIb (yp-T4N0M0).