Mesothelioma affects the mesothelium, the protective tissue that covers a number of organs in the body. There are several types of mesothelioma: each is named for the part of the body affected. The main three types of mesothelioma are:
- Pleural Mesothelioma
- Peritoneal Mesothelioma
- Pericardial Mesothelioma
Pleural mesothelioma is the most common form of this cancer, representing roughly three-quarters of all cases. Pleural mesothelioma affects the tissue that covers the lungs, and in most cases is caused by inhaling asbestos fibers. These fibers become trapped in the pleura and can cause scarring and inflammation. With pleural mesothelioma, asbestos can be inhaled up to 50 years before the cancer develops to a point where it is easily diagnosed.
A diagnosis of pleural mesothelioma is sometimes difficult to reach because of the number of more common diseases that can affect the lungs and present similar symptoms to those of pleural mesothelioma.
Peritoneal mesothelioma is the second most common form of mesothelioma, accounting for 10 to 20 percent of all mesothelioma cases. Peritoneal mesothelioma affects the tissue that lines the abdomen, and is normally caused when asbestos fibers are ingested. This could easily happen when an inhaled asbestos particle finds its way into the esophagus and becomes lodged in the digestive tract.
The latency period for peritoneal mesothelioma may be shorter than that of pleural mesothelioma, with symptoms presenting roughly 20 to 30 years after asbestos exposure.
The pericardium, or the tissue that surrounds the heart, is affected by pericardial mesothelioma, which accounts for less than 10 percent of all mesothelioma cases worldwide. As with other forms of mesothelioma, pericardial mesothelioma is caused by asbestos exposure. Pericardial mesothelioma may occur when cancer cells from pleural mesothelioma break through the pleura and into the pericardium. It is not currently clear exactly how inhaled or ingested asbestos fibers make their way to the pericardium, but genetics may play a factor in this type of cancer.