Pericardial Cyst

• Fluid-filled cysts of the parietal pericardium consisting of a single layer of mesothelial cells
• Usually discover at age 30-40 years, predominantly in males (3:2)
• Most are asymptomatic and incidental findings
• Atypical chest pain can occur
• They are usually (75%) located at the cardiophrenic angle almost always on the right (3:1)
• DDX of a right cardiophrenic angle mass
• Pericardial cyst
• Sequestration
• Foramen of Morgagni hernia
• They can occur higher and may extend into major fissure
• Classically they are soft and can be flattened on the edge that faces the fissure
• They rarely occur in the mediastinum
• Imaging findings
• Sharply marginated
• Round or oval mass
• From 3-8 cm in size usually
• They can change in size and shape with respiration or body position
• Rarely calcify
• On CT, their attenuation values of 20-40 HU, occasionally higher 

 
Pericardial Cyst. Frontal and lateral views of the chest demonstrate a mass at the right cardiophrenic angle with rim-like calcification that indicates the calcification has formed in the wall of a hollow viscus. This is a characteristic location for a pericardial cyst, which is calcified in this case.

Pericardial Cyst. Frontal view of the chest demonstrates a mass at the right cardiophrenic angle (black arrow) with smooth margins. The mass appears to abut the heart. A CT scan at a similar location shows a large, fluid-filled cystic structure (white arrow) The red arrow points to the heart.