Constrictive pericarditis with a life-threatening giant pericardial cyst and pectus excavatum as unusual cause for malign cardiac arrhythmias.

Pericardial cysts are rare, abnormal, benign and usually congenital anomalies with an estimated incidence of 1:100.000 and are caused by an incomplete coalescence of foetal lacunae of pericardium development. The size of pericardial cysts varies from 1 to 5 cm and generally do not cause any symptoms. Pectus excavatum is one of the most frequent chest wall abnormalities with a caved-in appearance of the chest and mostly of unknown pathogenesis. We present a rare case of constrictive pericarditis with a huge pericardial cyst (11.6 × 8.7 × 7.1 cm) and pectus excavatum which led to compression of the heart and life-threatening cardiac arrhythmias.