A large pericardial cyst complicated by a pericarditis in a young man with a mediastinal mass.

This is a case report of a 30-year-old man who presented with acute right-sided pleuritic chest pain. A chest roentgenogram performed in the emergency room shows a large, well-circumscribed transparent lesion obscuring the right heart border. Further imaging revealed a large pericardial cyst. The patient was taken to surgery as a result of clinical deterioration, and the knowledge that large pericardial cysts, although usually benign, can cause serious complications, including death. Pathology revealed an inflamed pericardial cyst with fibrinous pericarditis.