A rare giant pericardial cyst mimicking a paracardiac mass.

Pericardial cysts are rare benign lesions of the thoracic cavity and are mostly congenital anomalies. They are induced by an incomplete coalescence of foetal lacunae during the development of the pericardium. Pericardial cysts are usually unilocular, well marginated spherical or teardrop shaped and may be attached to the pericardium directly or by a pedicle. Of all pericardial cysts, 70 to 75% are located at the right cardiophrenic angle. We report a case that was incidentally diagnosed with only chest magnetic resonance imaging because of a paracardiac mass. In order to prevent complications, the giant pericardial cyst was excised outside of the pericardium with median sternotomy.