Pericardial cysts are an uncommon benign congenital anomaly in the middle mediastinum. They are thought to result from failure of fusion of one of the mesenchymal lacunae that form the pericardial sac. The authors present the case of a 77-year-old-man with a large pericardial cyst, treated by surgical resection trough a median sternotomy. They analyze the different diagnostic alternatives and the various management options in this pathology. In the reported case the authors used a surgical resection trough a median sternotomy, to facilitate the exposure of all of the cyst, extending around the great vessels area, and on the other side of the chest.