Mesothelioma and the Pericardium
Mesothelioma of the pericardium is extremely rare. It is a primary cancer of the pericardium, the layer of tissue that surrounds the heart, and because of this location is extremely difficult to treat.
Pericardial mesothelioma is so rare that exact numbers of cases are unknown. Some estimates put it at only 200 reported diagnoses ever. One study reviewed the medical literature and found only 27 cases of pericardial mesothelioma between 1972 and 1992. This accounts for about one percent of all known cases of mesothelioma.
Mesothelioma is a cancer of the mesothelium, the tissue that surrounds most organs in the body. The vast majority of cases are primary cancers of the pleura, the part of the mesothelium that surrounds the lungs because asbestos fibers are generally inhaled during exposure. Peritoneal mesothelioma, cancer of the tissue surrounding abdominal organs, is second most common.
Third most common is the cancer of the pericardium. The pericardium is a thin tissue, made up of two layers. The inner layer is called the visceral layer or the epicardium and the outer layer is called the parietal layer or the heart sac. Tumors may begin growing in either or both layers.
Causes and Risk Factors
Because this type of cancer is so rare, studies are limited and it is difficult to determine what causes it. Like pleural mesothelioma, causes are thought to be related to exposure to asbestos. There may be a component of environmental or genetic factors, but pericardial mesothelioma is simply too rare to be certain.
Having a family history of this cancer and being exposed to asbestos over a long period of time are the two strongest risk factors. It has also been found that men are twice as likely as women to have this type of cancer, likely due to workplace asbestos exposure.
Regardless of genetics or family history, asbestos exposure is the leading risk factor and most prevalent cause of any type of mesothelioma. This natural mineral is fibrous and when fibers come lose they can get into the air and be inhaled. They lodge in the lungs or pleura and over time can cause damage that leads to a number of illnesses, including cancer. People exposed to asbestos for years, usually at work, are at risk for mesothelioma, but not all will develop it.
Pericardial mesothelioma is also linked to asbestos exposure, but the connection is not as strong. It is not clear how the fibers of this mineral could get to the pericardium and cause a primary tumor there. It may be that fibers migrate from lung tissue to the area around the heart.
But the fact remains that rates of asbestos exposure among people diagnosed with pericardial mesothelioma are much lower than in those with pleural or peritoneal mesothelioma. Limited studies of people with pericardial mesothelioma have estimated that only about 15 to 30 percent of people getting the diagnosis were ever exposed to asbestos, as far as they know.
As with other types of mesothelioma symptoms, pericardial mesothelioma has a long latency period and symptoms often don’t appear until decades after any exposure to asbestos. In those cases with no asbestos exposure, symptoms still don’t seem to be troubling until the cancer has developed into later stages. Many of the symptoms of this type of mesothelioma result from the fact that it causes fluid to build up between the two layers of the pericardium and from a thickening of this tissue.
Potential symptoms that someone with pericardial mesothelioma may experience include:
- Heart Palpitations
- Trouble Breathing
- Weight Loss
- Shortness of Breath When Lying Down
- Chest Pains
- Cough (often dry and non-productive)
- Night Sweats
Patients may also experience:
- Heart Failure
- Swelling, of the Lower Limbs
Diagnosis of Pericardial Mesothelioma
The symptoms and the rarity of pericardial mesothelioma make it difficult to diagnose. The symptoms are often nonspecific and are caused by the fluid and thickening in the pericardium, both of which can be caused by other, more common conditions. A diagnosis will begin with a physical examination and medical history. The next step is most likely an image of the heart, usually by ultrasound, called an echocardiogram, which can show if there is fluid in the pericardium.
To image tumors, however, requires a better imaging scan. Radionuclide imaging is often used if tumors around the heart are suspected. This involves injecting the patient with a radioactive element, which is transported into cells that are rapidly dividing, like cancer cells. A radiologist can then see by detecting radiation, where in the body there are tumors.
The last step in a diagnosis is a biopsy of pericardium. Often times, even if the fluid is drained from around the heart, there will not be enough cancer cells to provide a diagnosis. A biopsy is the removal of a small amount of tissue from the area of the tumor that a pathologist will examine under microscopy. The pathologist looks for abnormal cells to try to determine if the abnormal tissue is a malignant tumor. Even with this diagnostic tool, getting a firm answer is difficult. In one study researchers were only able to find malignant cancer cells in four out of 17 cases of known pericardial mesothelioma.
Treatment for any type of mesothelioma is challenging, but this is especially true for pericardial mesothelioma. A surgery called a pericardiectomy is one possible option and involves removing the pericardium, either in part or completely.
In very early stages of the cancer this may cure it, but in most cases the cancer is too far advanced and this will only prolong the patient’s life a little. It can also provide some relief from the pressure of the fluid buildup.
Chemotherapy and radiation treatment are standard treatments for other types of cancer, but are not considered useful treatments for pericardial mesothelioma. For most patients, the focus is not on cure, but improving symptoms. Treatment most often involves palliative care to make the patient more comfortable. Removing fluid and parts of the pericardium, for instance, relieve pressure on the heart and reduce pain and other symptoms.
The overall prognosis for pericardial mesothelioma is very poor, with median survival at 5-7 months from diagnosis. Treatment most often involves palliative care to make the patient more comfortable. Removing fluid and parts of the pericardium, for instance, relieve pressure on the heart and reduce pain and other symptoms.
Page Medically Reviewed and Edited byLuis Argote-Greene, M.D.
Luis Argote-Greene is an internationally recognized thoracic surgeon. He has trained and worked with some of the most prominently known thoracic surgeons in the United States and Mexico, including pioneering mesothelioma surgeon Dr. David Sugarbaker. He is professionally affiliated with University Hospitals (UH). His areas of interest and expertise are mesothelioma, mediastinal tumors, thoracic malignancies, lung cancer, lung transplantation, esophageal cancer, experimental surgery, and lung volume reduction. Dr. Argote-Greene has also done pioneering work with video-assisted thoracoscopic surgery (VATS), as well as robotic assisted minimally invasive surgery. He has taught the procedures to other surgeons both nationally and internationally.