A 59-year-old male patient was diagnosed with advanced esophageal cancer in September, 2002. He received 1 course of chemoradiotherapy. A chest radiograph performed upon admission revealed left lower lobe pneumonia with left-side pleural effusion, pulmonary edema, and cardiomegaly. The chest X-ray follow-up revealed apparent pneumopericardium. A chest computed tomography showed esophageal cancer with pneumopericardium. An esophagogram revealed an esophagopericardial fistula connected between the lower esophagus and the pericardial sac. Accompanying this case report, we review the literature concerning the various etiologies of pneumopericardium, the clinical features, diagnostic techniques, and principles of management.