Key points
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Pericardial tumors can be benign or malignant. Of the benign pericardial tumors, pericardial cysts are the most common. Other benign pericardial tumors include angiomas, lymphangiomas, fibromas, teratomas, and lipomas.
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Primary malignant pericardial tumors include mesotheliomas, lymphomas, thymomas (may be benign or malignant), sarcomas, and liposarcomas.
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Metastatic pericardial tumors occur 20 to 40 times more common than primary pericardial tumors and mostly result from the direct extension of tumors, principally the lung and the breast, producing a pericardial effusion that can progress to cardiac tamponade.
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Echocardiography, computed tomography, and magnetic resonance imaging are diagnostic modalities for detecting pericardial masses ( Box 25.1 ).
Box 25.1
Primary pericardial tumors are rare and may be classified as benign or malignant. The most common benign lesions are pericardial cysts and lipomas. Mesothelioma is the most common primary malignant pericardial neoplasm. Other malignant tumors include a wide variety of sarcomas, lymphoma, and primitive neuroectodermal tumor. When present, signs, and symptoms are generally nonspecific. Patients often present with dyspnea, chest pain, palpitations, fever, or weight loss.
The diagnostic workup often starts with transthoracic echocardiography (TTE), which usually identifies the mass. Further evaluation using transesophageal echocardiography (TEE) may be indicated to complement the TTE assessment. Often, investigation with other imaging modalities such as CT, CMR, or PET is warranted for more detailed assessment by visualization of the entire pericardium, tissue characterization, and evaluation of surrounding structures. Although imaging may help in the identification and characterization of the mass, a biopsy is often needed for definitive tissue diagnosis .
Information on whether a mass is malignant or benign is important to direct surgical versus medical management. In addition, the extent of cardiac and extracardiac involvement is also important to determine the potential for complications such as pericardial effusion with or without cardiac tamponade, constrictive pericarditis . Large masses deemed to be benign based on imaging can often be completely surgically excised to not only provide tissue for pathologic analysis, which remains the gold standard for definitive identification but also to provide symptom relief .
Small masses may be best assessed using CT given its high spatial resolution while larger masses may be better assessed using CMR due to its superior tissue characterization abilities . Progression of the disease can be assessed using TTE if there are optimal acoustic windows or using CT or CMR if not easily visualized by TTE while the metabolic response to treatment can be evaluated using PET .
Pericardial masses are relatively rare and are mostly caused by malignancies. The metastatic involvement of the pericardium is more frequent than that by primary tumors and often carries a poor prognosis. Inflammatory and infectious diseases are very rarely reported as causes of pericardial masses in the literature, with a few reports of cardiac echinococcosis, rheumatoid arthritis, inflammatory pseudotumors, and tuberculous pericarditis. The presentation varies, and patients are often asymptomatic, with pericardial involvement detected only at the autopsy or as an incidental finding during thoracic imaging tests. Some patients, however, may develop progressive symptoms of venous congestion due to the evolution of pericardial effusion (diastolic restriction) or constriction, presenting with dyspnea, orthopnea, and peripheral edema .
Pericardial cysts are rare congenital anomalies located in the mediastinum. They are usually asymptomatic; nonetheless, they rarely produce symptoms based on their location and size. Commonly, they are located in the right cardiophrenic angle, followed by the left, anterosuperior, and posterior mediastinum. They are usually unilocular, well-marginated, spherical-shaped cysts lined with a single layer of mesothelial cells histologically. Most cysts are asymptomatic, but occasional complications include the obstruction of the right ventricular outflow tract, the obstruction of the main bronchi and atelectasis, cardiac tamponade, and sudden death. Imaging modalities include echocardiography, CT, and MRI. Usually, close follow-ups are sufficient in asymptomatic patients. Percutaneous drainage and surgical resection are the usual treatment modalities for symptomatic individuals .
| Lesions | Differentiating features |
|---|---|
| Bronchial cysts | Lined with the bronchial epithelium |
| Localized pericardial effusions | Fluid between the visceral and parietal pericardium |
| Teratomas | Usually associated with some solid components along with cystic components |
| Neurenteric cysts | Located in the right posterior chest and associated with vertebral anomalies |
| Lymphangiomas | Multilocular or multiple cysts |
| Congenital cysts of primitive foregut origins (e.g., bronchogenic cysts, gastroenteric cysts, and esophageal duplication cysts) | Usually located in the posterior mediastinum and lined by the epithelium |
| 1. Congenital |
| 2. Inflammatory (e.g., rheumatic pericarditis, bacterial infection, particularly tuberculosis, and echinococcosis) |
| 3. Traumatic |
| 4. Postcardiac surgery |
| 5. Patients on chronic hemodialysis |
| Characteristics | A homogeneous echolucent mass with minor attenuation of the ultrasound through a low-density fluid-filled structure An echo-free space, indicating its separation from the cardiac chambers |
| Advantages | Safe Low cost May be performed on unstable patients Diagnostic modality for follow-ups and image-guided percutaneous aspiration |
| Disadvantages | Limited windows and narrow fields of view Technical difficulties in patients with obesity or obstructive lung disease, as well as in patients immediately post cardiothoracic surgery Difficulty in the localization of cysts at uncommon locations Operator dependent |
Typically, pericardial cysts appear on CT images as well-defined, nonenhancing, homogeneous fluid-attenuation lesions that contain no internal septa. On CT, these thin-walled, homogeneous structures are nonenhancing with iodinated contrast and have an attenuation between − 10 and 20 HU. Occasionally, the cyst may contain proteinaceous fluid, in which case the lesion will demonstrate intermediate attenuation at CT. Pericardial cysts with hemorrhagic contents appear with hyperattenuation at CT .
