Pericardial Cyst
A pericardial cyst is a benign, fluid-filled lesion that arises from the pericardium, the thin sac surrounding the heart. Pericardial cysts are typically congenital and are most often discovered incidentally on chest imaging done for other reasons. They are usually located at the right cardiophrenic angle, where the heart meets the diaphragm. Most pericardial cysts cause no symptoms and require no treatment, while larger or symptomatic cysts may need closer evaluation and, in selected cases, drainage or surgical removal.
What is it?
The pericardium is the thin, two-layered sac that surrounds the heart and the roots of the great vessels. It contains a small amount of fluid that allows the heart to move smoothly within the chest as it beats. A pericardial cyst is a benign, fluid-filled lesion that arises from the pericardium, most often during early fetal development when small pockets of pericardial tissue close off and form an isolated cyst. They contain clear, watery fluid and are typically lined by cells similar to those of the pericardium.
Pericardial cysts are most commonly located at the right cardiophrenic angle—the area where the right side of the heart meets the diaphragm—but they can also occur on the left side or in other locations along the pericardium. They vary in size, from small (a few centimeters) to occasionally large lesions. They are almost always benign and tend to remain stable or grow only slowly over time.
The majority of pericardial cysts cause no symptoms and are discovered incidentally on a chest X-ray or CT done for other reasons. When symptoms occur, they are typically related to the cyst’s size and location, particularly if it is pressing on adjacent structures such as the heart, lungs, or great vessels. Possible symptoms include vague chest discomfort, cough, shortness of breath, palpitations, or, more rarely, lightheadedness. Uncommon complications include infection within the cyst, bleeding into the cyst, sudden growth, or rupture into the pericardial space, which could cause more pronounced symptoms.
Chest X-ray may show a smoothly rounded mass at the cardiophrenic angle. CT of the chest with intravenous contrast is the primary imaging test for evaluating a suspected pericardial cyst because it provides detailed information about size, location, density (typically uniform low density consistent with fluid), and relationship to nearby structures. The characteristic appearance often allows for confident diagnosis based on imaging alone. MRI provides excellent soft-tissue contrast and can confirm the fluid nature of the lesion, which is particularly helpful when the CT appearance is atypical. Echocardiography is useful for evaluating the heart and pericardium and can sometimes visualize the cyst, especially when it is adjacent to the heart. In selected cases, additional imaging or biopsy may be needed when the diagnosis is uncertain.
Important to Know
Management of pericardial cysts is individualized based on size, location, symptoms, and the degree of certainty about the diagnosis. The great majority of small, classically appearing pericardial cysts are benign and require no specific treatment. In these cases, the most important step is establishing the diagnosis confidently—often based on imaging features alone—and reassuring the patient. Follow-up imaging may be considered, particularly initially, to confirm stability over time.
For larger cysts, those causing symptoms, those with atypical imaging features, or those that grow significantly on follow-up, intervention may be considered. Options include image-guided aspiration of cyst fluid (which can provide symptomatic relief but is associated with recurrence in many cases) or surgical removal, often through minimally invasive techniques such as video-assisted thoracoscopic surgery (VATS) or robotic surgery. Surgery is generally preferred when symptoms are clearly attributable to the cyst, when the diagnosis is uncertain, or when complications such as infection or rupture have occurred.
Care is typically coordinated by primary care clinicians, cardiologists, and thoracic surgeons. Imaging findings are interpreted alongside the patient’s symptoms, examination, and broader clinical context rather than in isolation.
Because pericardial cysts are benign and most cause no symptoms, the goal of evaluation is to confirm the diagnosis, exclude more serious mediastinal conditions that can sometimes appear similar (such as other mediastinal cysts, lipomas, or, rarely, tumors), and decide whether any further action is needed.
Red flag symptoms include sudden severe chest pain, rapidly worsening shortness of breath, palpitations with lightheadedness or fainting, fever with chest pain, signs of cardiac tamponade (such as low blood pressure and significant breathing difficulty), or sudden change in known cyst symptoms. These warrant prompt or urgent medical evaluation.