Giant calcific pericardial cyst: certainly unexpected during primary percutaneous coronary intervention.

Pericardial cyst is a rare congenital anomaly that is usually diagnosed during evaluation for right-sided heart failure. We report a 50-year-old man with a primary diagnosis of ST-segment elevation myocardial infarction at admission, whose emergent angiography revealed a calcific mass close to right coronary artery. Further analysis of the mass with computed tomography and three-dimensional echocardiography revealed a giant pericardial cyst causing partial obstruction of superior vena cava. Unlike previous cases reported, the patient had no symptoms compatible with right-sided heart failure.