Mesothelioma is a rare cancer that affects the mesothelium, the inner membrane that protects the heart, chest and abdominal cavity. Here's a look at the three different types of this uncommon, but deadly chronic health condition:

Pleural Mesothelioma

Pleural mesothelioma, the most common type of mesothelioma, primarily affects the lining of the lungs. It has been estimated that nearly 75 percent of all mesothelioma cases are cases of pleural mesothelioma. It should be noted that this is not a form of or related to primary lung cancer. With pleural mesothelioma, the serous membranes of the lungs are the target of the cancer cells. These membranes are crucial to protecting the body's other internal organs, particularly those near the abdominal area.

This type of mesothelioma is contracted through the inhalation of asbestos fibers in the workplace or any that are still lingering on clothing. These fibers then settle in the pleura, or lining, of the lungs. Over time, these fibers may cause chronic inflammation, which can lead to the development of cancer cells and tumors over time. This is why it may take anywhere from 20 to 50 years for symptoms to appear. Possible warning sign symptoms include chest pain, difficulty breathing, coughing and unexpected weight loss.

The chronic inflammation may lead to asbestosis, which is a type of asbestos lung disease. Although many have called pleural mesothelioma lung cancer asbestos lung cancer, this name is inaccurate. Pleural mesothelioma affects the membranes of the lung, while the lungs are directly affected with in asbestos lung cancer or asbestos lung disease.

Peritoneal Mesothelioma

The second most common mesothelioma cancer is peritoneal mesothelioma, which accounts for almost 10 percent of all mesothelioma cases. This type of mesothelioma particularly affects the abdominal lining, which is known as the peritoneal. The peritoneal helps to protect the organs located within the abdominal cavity; in addition, it ensures that those organs are properly lubricated to allow them properly function and shift around as needed.

Symptoms for peritoneal mesothelioma may include abdominal pain, unexpected weight loss, nausea and vomiting, appetite loss, abdominal swelling and bowel obstruction. Other common mesothelioma symptoms are difficulty in breathing, as well as any unusual, extreme pain.

Pericardial Mesothelioma

The third type of mesothelioma affects the pericardium, the lining of the tissue surrounding the hart. Pericardial mesothelioma is the most rare form of mesothelioma.

Doctors and researchers are still unsure of how asbestos fibers make their way to the pericardium, as the inhalation of asbestos fibers typically affects the membrane around the lungs first. It has been suggested that these asbestos fibers work their way from the lungs, to the pleura, and lastly, attack the membrane of the pericardium. Others believe that these fibers are instead carried out of the lungs by blood and become lodged within the heart lining as blood is being pumped. As a result, cancerous tumors may begin to develop and grow around the heart. Key pericardial mesothelioma symptoms include an irregular heartbeat and chest pain, as well as coughing and difficulty in breathing.