Pericardial cysts are considered rare incidental findings, which are generally asymptomatic in nature. Occasionally, patients may represent with chest discomfort, dyspnea, or palpitations. Pericarditis related to a ruptured pericardial cyst has not been previously reported in the literature. Here, we report the case of a 62‐year‐old man who developed acute pericarditis as a result of a ruptured enlarging pericardial cyst.