We report a case of partial resection of the hemisternum of a thymic carcinoma invading the right anterior chest wall. A computed tomographic scan of the chest and positron emission tomography showed a mass invading the right anterior chest wall in the anterior mediastinum with high 18F-fluorodeoxyglucose accumulation. An operation was performed to obtain a definitive diagnosis and achieve complete resection. First, we assessed the boundaries of gross disease using left-sided video-assisted thoracoscopy. After delineating the margins of the lesion invading the anterior chest wall, a median sternotomy was added and the tumor was resected with the right half of the sternum, parts of the right third and fourth costal cartilages, part of the right upper lung lobe, and pericardium. Histopathological evaluation revealed a squamous cell carcinoma of the thymus with direct invasion to the right lung, pericardium, and the right third costal cartilages.