A large pericardial cyst compressing the left atrium presenting as a pericardiopleural efussion.

Pericardial cysts are rare congenital abnormalities with a reported incidence rate of 1:100,000, accounting for about 7.6% of all mediastinal masses. These cysts frequently occur in the right cardiophrenic angle and their diagnosis is usually suspected after an abnormal chest X-ray is obtained.

Congenital partial defect of the left pericardium presenting as chest pain.

Congenital pericardial defect is a rare cardiac defect with variable clinical presentations. It is usually an unexpected finding during cardiac surgery or autopsy. The clinical detection of congenital absence of pericardium is important because of its life-threatening complications such as fatal myocardial strangulation, myocardial ischaemia and sudden death.