Pericardial mesothelioma is the rarest form of asbestos-caused cancer.
Tumors first form in the lining of the heart (pericardium).
Often, pericardial mesothelioma is not diagnosed until an autopsy is performed.
Despite having the worst prognosis, there are some treatment options.
Pericardial mesothelioma is an extremely rare form of the disease, accounting for only 1 – 2% of all mesothelioma diagnoses. Pericardial mesothelioma originates in the pericardium, the double-layered membrane that lines the heart. In some instances, the cancer has presented as secondary tumors caused by other forms of mesothelioma and other metastatic cancers.
As the rarest form of mesothelioma, research is more limited, making diagnosis difficult and limiting treatment options.
- Cause // Asbestos inhalation or ingestion
- Location // Heart lining (pericardium)
- Common Symptoms // Chest pain
Pericardial effusion (fluid buildup)
- Treatment // Surgery
- Prognosis // 6 months
What Causes Pericardial Mesothelioma?
While the majority of all mesothelioma cases can be directly linked to asbestos exposure, researchers are not as convinced this rare form of the disease is as closely associated with the toxin. A recent study observing 103 reported cases of pericardial mesothelioma between 2000 and 2016 found only 25% of the patients had a history of asbestos exposure.
Some researchers argue that the most common cause of pericardial mesothelioma is through metastasis, with several studies stating that primary pericardial mesothelioma is extremely rare and may even be benign. Some studies have observed pericardial tumors as a result of either primary pleural mesothelioma or peritoneal mesothelioma, as well as other types of cancer like adenocarcinomas, lung cancer, leukemia, breast cancer or melanoma.
For cases that can be linked to asbestos, researchers are still unsure as to how the asbestos fibers reach the pericardium. Medical examiners have noted asbestos fibers found in the pericardium in some autopsy reports, but there is not enough evidence available to determine how the mineral was able to navigate to the heart.
Diagnosing the Symptoms of Pericardial Mesothelioma
Pericardial mesothelioma tumors develop between the two layers of the mesothelium. Research has shown the tissue first begins to scar and thicken, which restricts the movement of the heart muscles. Some patients may also experience pericardial effusion, where fluid builds up around the heart and even further impairs its function.
Because these tumors are so damaging, patients often experience severe symptoms even before the disease has progressed to later stages. In some instances, however, patients may not experience many symptoms at all before the cancer kills them because of the long latency period and how quickly the heart’s function becomes impeded from the aggressive mesothelioma tumors.
- Chest pain
- Dyspnea (difficult, labored breathing)
- Pericardial effusion
- Tachycardia (abnormal, rapid heart beat)
- Cardiac tamponade (compression of the heart from excess fluid)
- Heart murmurs
- Arrhythmias (irregular heartbeat)
- Tachycardia (abnormal, rapid heart beat)
- Constrictive pericarditis (chronic inflammation of the pericardium)
- Visible jugular venous pulse
- Hypotension (low blood pressure)
- Cardiac failure
Like with other forms of mesothelioma cancer, symptoms are nonspecific and can worsen quickly because of the cancer’s aggressive nature, hindering the ability to make an accurate differential diagnosis. As arguably the most aggressive form of mesothelioma because of its location, many patients unfortunately are not even properly diagnosed until an autopsy is performed posthumously.
However, ante-mortem diagnosis is not altogether impossible, as some recent studies have explored new diagnostic techniques that can help differentiate pericardial mesothelioma from other pericardial tumors and diseases. Reports have shown that pericardial mesothelioma can be mistaken for other cancers like adenocarcinomas, angiosarcoma, lymphoma and carcinoma. It has also been misdiagnosed as non-cancerous conditions including heart disease, tuberculous pericarditis and lupus.
As with other forms of malignant mesothelioma and cancer, imaging tests are typically the first step of diagnosis. Irregularities in the chest cavity, like pericardial effusions or any visible tumors, are usually first noticed in an x-ray or CT scan. A chest CT scan or PET scan can show any tumor masses around the heart or fluid buildup with more detail and accuracy, which can help lead to an appropriate diagnosis.
A biopsy is the only way to definitively confirm a diagnosis. Doctors may take a tissue sample or a sample of the pericardial effusion to analyze. In addition to the usual histology (determining the cell type) and cytology (how the mesothelioma cells function and spread) reports, doctors also often need to go through the immunohistochemistry process to confirm diagnosis.
Immunohistochemistry is a type of stain that uses specific antibodies to target specific antigens or proteins in the sample that can help identify mesothelioma, like cytokeratin, WT-1 protein and other mesothelial markers. The antibodies will bind to these antigens, which can then be viewed under a microscope. Mesothelioma biomarkers like calretinin and mesothelin are important for determining a correct diagnosis.
Pericardial Mesothelioma Stages
Like peritoneal mesothelioma, pericardial mesothelioma has no clear staging system because of its rarity. Additionally, because the cancer is so aggressive, many patients aren’t diagnosed until posthumously or when the cancer is more advanced with limited treatment options.
Though there is no defined staging system for pericardial mesothelioma, researchers can base how advanced the cancer has become on more general characteristics.
The mesothelioma is localized with no metastasis. Mesothelioma patients have more treatment options, including curative surgery. Patients diagnosed at this stage have the best prognosis.
The cancer is still localized, but may have metastasized to some nearby tissue and organs or the lymph nodes. Patients still have curative treatment options available, including surgery depending on how much and where the cancer may have spread.
The mesothelioma has more distant spreading to areas beyond the original tumor, though is still localized to one side of the body. Cancerous cells have also spread to the lymph nodes. At this point, treatment options may be limited to palliative care.
Cancer cells have spread distantly to both sides of the body. Because of such severe progression, surgery is not an option and patients can only receive palliative treatments to relieve symptoms and improve quality of life.
Because there are so few reported cases, specialists don’t have a clear understanding of how pericardial mesothelioma may spread in the body. Some case reports have noted that the mesothelioma cells may spread throughout the heart and pulmonary artery, which could then help the cancer flow anywhere in the body to more distant organs. Many studies, however, have attributed pericardial mesothelioma tumors as secondary or metastatic tumors themselves.
Across several of these studies, researchers have been able to note some of the common organs metastatic pericardial mesothelioma may reach.
- Chest wall
- Abdominal cavity
- Lymphatic system
Pericardial Mesothelioma Prognosis
Because of the cancer’s rarity, malignant pericardial mesothelioma patients face the worst prognosis of all three types. It has proven especially difficult to detect this form of the asbestos cancer early, and researchers remain unsure as to the best treatment options to possibly extend life expectancy.
One recent study found an average life expectancy of just 5.6 months across 103 pericardial mesothelioma cases. Some case reports have recorded survival of just a few weeks after diagnosis, even in a clinical study of a patient who was able to have his tumors resected.
In addition to the location of the disease, stage, the type of mesothelioma cell, age, gender, and a patient’s overall health are just some factors that can impact prognosis and the types of treatment available.
Pericardial Mesothelioma Treatments
Treatment options for pericardial mesothelioma are limited, as there have been too few cases for researchers to understand the most effective treatment or combination of therapies. Clinical trials for pericardial mesothelioma are also almost nonexistent for the same reason, though researchers may be able to apply new treatment techniques that have shown success in other similar cancers.
In recorded cases, doctors have mostly relied on conventional treatments of surgery, chemotherapy and radiation therapy for pericardial mesothelioma patients. In a few rare cases, patients have been able to undergo surgery to remove or reduce localized tumors in a curative or palliative manner. There are a few types of surgeries mesothelioma specialists may utilize for eligible patients.
This surgery, sometimes referred to as pericardial stripping, removes part or all of the pericardium. The intent is to remove any visible tumors, and hopefully many of the cancerous cells to prevent growing and spreading of the disease. As a major cardiac procedure, this is only an option for patients diagnosed at earlier stages with better overall health to withstand the aggressive operation.
This procedure removes excess fluid in the pericardium to relieve pressure on the heart and improve functionality. While not considered curative, pericardiocentesis can greatly improve quality of life by alleviating symptoms.
Sometimes referred to as PBP, this surgical procedure also helps remove pericardial effusions. A long, thin tube is inserted into the pericardium and uses a balloon to separate the thin layers of the membrane, allowing the excess fluid to drain and help prevent future fluid buildup.
In addition to surgery, standard chemotherapy treatment of pemetrexed and cisplatin has also been used in some cases to reduce tumor mass and help alleviate symptoms. In a 2017 review of over 100 pericardial mesothelioma cases, researchers noted that 37% of the patients underwent the chemotherapy combination with extended survival.
Radiation therapy has also been applied, but hasn’t shown any evidence of effectively treating or delaying spread of the disease. For some patients, it may help as a palliative procedure to alleviate some symptoms.
Again, clinical trials for this form of mesothelioma are limited because of the cancer’s rarity, but researchers are working to test the efficacy of other promising treatments, like immunotherapy and photodynamic therapy, for pericardial mesothelioma.