Incidental finding of congenital pericardial and mediastinal pleural defect by pneumothorax in an adult

Introduction: Congenital pericardial defect (CPD) is an uncommon anomaly. If once cardiac herniation occurs, it threatens life. We report a case of left-sided pneumothorax with consequent protrusion of the heart into left thoracic cavity through not only a large CPD but also congenital pleuropericardium window. Case presentation: A 67-year-old man presenting with sudden-onset left-sided chest pain and slight dyspnea was referred to our hospital. Chest X-ray showed a left lung collapse, and also revealed a pneumopericardium along the right border of the ascending aorta. Subsequent computed tomography (CT) scan revealed that the heart was displaced into the left hemithorax. Thus, we diagnosed the patient with pneumothorax and a defect of the pericardial and mediastinal pleurae. Subsequently, a chest tube was inserted into the left thoracic cavity, and the collapsed lung was promptly inflated. The cardiac position was reinstated within mediastinum as evidenced by follow-up CT scan. The QRS axis on his electrocardiogram (ECG) was altered from 52° to 73°. Together with the cardiac relocation evidenced by the QRS axis shift on ECG and findings of CT, we determined that there was a low potential for complications and opted against surgical repair. Discussion: When the CPD is sufficiently large, surgical intervention is not necessary. The size of the CPD can be assessed not only by CT findings, but the alteration of the QRS axis on ECG also provides useful information whether cardiac herniation can be resolved by the inflated lung.