We present the clinical case of a 60-year-old woman complained of dyspnea on exertion. Echocardiogram showed a giant mass in right ventricle (RV) with obstruction to the outflow tract. Thorax CT confirmed a mass of >60 mm infiltrating RV and causing severe stenosis in pulmonary artery, with severe pericardial effusion. Cardiac surgery was performed for tumor resection and pulmonary root replacement with a biological valved conduit. Histological analysis diagnosed a poorly differentiated large-cell neuroendocrine carcinoma. The patient had no immediate postoperative complications and has completed radiotherapy at 6-month follow-up.