- Outpouching of the parietal pericardium that is lined by mesothelial cells.
- Usually unilocular.
- Most commonly detected incidentally in asymptomatic patients
- Most common location is the right costophrenic angle
 Differential Diagnosis
- Fat pad
- Cardiac lipoma
 Imaging Findings
- Smoothly and sharply marginated mass
Patient #1: Pre-employment chest x-ray
Patient #2: MRI demonstrates a pericardial cyst