We present a case of a large thymoma with invasion to the hilum of the lung and pleural dissemination. A 58-year-old woman was diagnosed with a type B2 thymoma, with suspected pericardium, pulmonary artery and left lung invasion and pleural metastasis (Masaoka-Koga stage IVb). A radical resection was planned after systemic chemotherapy. Through a median sternotomy, we resected the tumour, and after confirmation of pericardium and left lung invasion, we also performed resection of the pericardium, of the lung and of the pleural metastasis. The median sternotomy allowed a safe dissection of pulmonary vessels and main bronchus.