Chest X-rays revealed an abnormal shadow without symptoms such as hoarseness, in a 74-year-old man with a history of rheumatoid arthritis. Chest CT and MRI revealed an irregularly shaped mediastinal tumor measuring 60 × 60 × 55 mm that obstructed the left innominate vein and suspected invasion of the aortic arch. A CT-guided percutaneous needle biopsy revealed squamous cell carcinoma of the thymus that was considered unresectable. Since PET-CT and brain MRI ruled out metastatic lesions, such as mediastinal lymph node and brain metastases, the tumor was diagnosed as local advanced thymic carcinoma, Masaoka stage III, cT4N0M0 stage IIIB. The patient underwent six cycles of chemotherapy (three cycles each of ADOC and carboplatin/paclitaxel), which decreased the tumor to 55 × 55 × 50 mm on CT images (Fig. 1a, b) and the disease was defined as stable (SD), according to the RECIST criteria. Two months later, the patient was referred to us for consideration of surgical resection. We applied a radical surgical procedure through a median sternotomy and left lateral thoracotomy. Neither pleural/pericardial dissemination nor malignant effusion was evident. The tumor was located in the anterior mediastinum and had invaded the aortic arch around the root of the brachiocephalic artery (Fig. 2a), which rendered partial resection of the aortic arch unsuitable. Therefore, we replaced the entire aortic arch to achieve complete resection. The left brachiocephalic vein (LBCV), as well as the phrenic and vagal nerves, was resected; then, we encircled the distal sides of the brachiocephalic, left common carotid (LCCA), and left subclavian (LSCA) arteries, as well as the superior vena cava (SVC), ascending (AA), and descending aorta. Thereafter, a cardiopulmonary bypass (CPB) established with cannulation of the left femoral artery, right axillary artery, right femoral vein, and SVC was followed by deep hypothermic circulatory arrest with a bladder temperature of 23 °C. Thereafter, the tumor, aortic arch and three vessels were resected. The aortic arch was reconstructed using a 26-mm woven shield vascular prosthesis (Fig. 2b). The surgical duration was 678 min, blood loss was 3180 g, CPB duration was 175 min, including 81 and 31 min of cardiac and circulatory arrest, respectively. We did not use a cell salvage device. The postoperative course was uneventful, with durations of ventilation and stay in the ICU of 4 and 6 days, respectively. Figure 3a shows the macroscopic appearance of the resected tumor. The final pathological findings of the tumor were squamous cell carcinoma, ypT4N0M0, stage IIIB, and intra-tumoral fibrous stromal change surrounded by viable cancer cells. Viable cells were also scattered in the aortic adventitia (Fig. 3b), although the cut margin was pathologically negative. The patient remains alive and free of recurrence at over 3 years after surgery.
