Pericardial cysts are rare mediastinal masses commonly asymptomatic and incidentally found on chest radiographs. Pericardial cysts may be acquired/inflammatory in origin and may be symptomatic. We present a case of 65-year-old male who presented with symptoms of right heart failure. Diagnosis of a giant pericardial cyst was made using imaging modalities such as chest X-ray, computed tomography scan, and echocardiography. Percutaneous cyst aspiration was done under echocardiography guidance. Radiologists and cardiothoracic surgeons need to understand the pathology of inflammatory/acquired pericardial cysts to include in their differential diagnosis of mediastinal masses