Pericardial Cysts are very rare benign congenital anomalies of the anterior and middle mediastinum with incidence of about 1 in 100,000. 60% are discovered between the ages of 30 to 50 and over 75% of them are right-sided, 22% are left-sided, while the rest are in the posterior or anterior superior mediastinum. Pericardial Cysts are thought to result from the failure of fusion of one of the mesenchymal lacunae that forms the pericardial sac, unfortunately due to the lack of research the true cause is unknown. Most discovered pericardial cysts are incidentally, usually in a chest x-ray or CT scan for a different condition. Consquintly though if the pericardial cyst does cause symptoms, they are usually due to compression of adjacent organs.
