There are four primary types mesothelioma based on the location where a tumor first develops: pleural (lungs), peritoneal (abdomen), pericardial (heart), and testicular. In addition, mesothelioma can be categorized based on cell type – epithelioid, sarcomatoid, or biphasic – and according to malignancy.
Types Mesothelioma by Location
The thin tissue lining where mesothelioma develops, known as the mesothelium, is located in certain areas of the body, such as the area of the chest surrounding the lungs and the abdominal cavity. The most common way to classify mesothelioma is to determine where in this mesothelial layer the disease originates.
Pleural Mesothelioma (Lungs)
Pleural mesothelioma develops in the lining of the lungs (known as the pleura). As the most common form of the disease, pleural mesothelioma accounts for approximately 80% of new cases.
Pleural mesothelioma is hard to diagnose. In the early stages of the disease, symptoms tend to be mild, while in later stages (stage 3 or stage 4) symptoms can worsen significantly. Unfortunately, since it is often diagnosed at a later stage, mesothelioma usually has a poor prognosis – most patients live less than 17 months from the time that their first symptoms appear.
Peritoneal Mesothelioma (Abdomen)
Peritoneal mesothelioma originates in the lining of the abdomen. It often spreads to abdominal organs, including the liver, spleen, and bowel. Severe abdominal pain is the most common symptom, followed by discomfort caused by fluid buildup (abdominal effusion).
Although the prognosis for peritoneal mesothelioma is poor, it has improved somewhat in recent years, largely due to new treatments such as hyperthermic intraperitoneal chemotherapy (HIPEC). Outcomes vary from patient to patient, however, and survivorship typically depends on the individual’s situation and specific diagnostic factors.
Pericardial Mesothelioma (Heart)
Pericardial mesothelioma, which originates in the lining of the heart cavity (the pericardium), is uncommon – accounting for less than 1% of all mesothelioma cases. As this rare cancer progresses, the heart becomes unable to deliver oxygen to the body, causing further decline in health at an increasingly rapid rate.
The most common symptoms of pericardial mesothelioma mimic those of a heart attack, including pain in the chest and shortness of breath. In many cases, pericardial mesothelioma goes undiagnosed until an autopsy is performed.
Testicular mesothelioma is an extremely rare form of the disease, with fewer than 100 cases having been diagnosed around the world. Because there are so few incidents of this type of mesothelioma, little is understood about how it develops, and there is no standard course of treatment available.