Pericardial mesothelioma is also known as mesothelioma of the pericardium or cancer of the sac that holds the heart. Your doctor may diagnose pericardial mesothelioma using a thoracoscope to perform a thoracoscopy, which might also involve opening up the chest cavity to remove the tumor.

Patients who develop excessive fluid around the heart, called an effusion, may have a sample of the fluid taken to diagnose pericardial mesothelioma.