A 57-year-old man was admitted to the hospital because of multiple subcutaneous masses with pain, mild dyspnea, and bloody sputum. He had been asymptomatic until one month earlier, when he began to have a dry cough and myalgia of the right forearm. A chest radiograph showed cardiomegaly. Whole-body computed tomographic scan, cytologic examination of the sputum, and histological examination of a subcutaneous nodule on the scalp resulted in the diagnosis of lung cancer with multiple organ metastases, including those to skeletal muscle and myocardium. Despite chemotherapy, he died suddenly on the 45th hospital day. Autopsy revealed that about half of the myocardium had been replaced by metastatic tumors, so we speculated that he died from heart failure due to cardiac muscle metastasis.