They are rare congenital abnormalities incidence rate is 1/100,000 males.. The most common locafions are middle mediastinum and right cardiophrenic angle. Pericardial cyst are usually asymptomatic unless a complication or rapid growth occurs. Diagnosis:: using combine radiological x ray, contrast computed tomography or CT , echocardiography, Treatment:::observation, needle aspiration, surgical excision of the cyst