A Case of Sudden Death by Sinoatrial Nodal and Myocardial Metastasis from Primary Lung Cancer

Background. Case of cardiac metastasis from primary lung cancer have sometimes been reported. However, among these, myocardial metastasis is uncommon and sinoatrial nodal metastasis is even less common. Case. The X-ray film of an 81-year-old man showed a mass shadow in his right upper lung field in July 2007, but no therapy was given. In January 2009 he developed bloody sputum, but a bronchoscopic examination in March 2009 did not yield a definitive diagnosis. However, we strongly suspected primary lung cancer in right upper lobe based on his PET/CT findings in April 2009, and radiation therapy was initiated. While he was being treated at an outpatient clinic, he developed radiation pneumonitis and was admitted to our hospital in September 2009. His radiation pneumonitis improved, but he suddenly died on the 40th day after admission. The autopsy findings revealed pleomorphic carcinoma with adenocarcinoma components in his right upper lobe, sinoatrial nodal metastasis, and multiple myocardial metastases. In addition, a 2-cm bronchioloalveolar carcinoma was found in his right middle lobe. Therefore, we diagnosed multiple primary cancers. Conclusion. The cause of his sudden death was considered to be arrhythmia due to sinoatrial nodal metastasis from primary lung cancer. The clinical course of this case was unique compared with those of common lung cancer cases, and this case involved rare sinoatrial nodal metastasis from the patient's lung cancer.