Pleural mesothelioma is a rare type of cancer. This cancer affects the pleural sac that surrounds the lungs and is caused by exposure to asbestos. The pleural sac contains the lungs and also a small membrane called the mesothelium.

The mesothelium secretes a fluid that allows the lungs to contract and expand during breathing. The inhalation of asbestos causes a build-up of asbestos fibers inside the lungs. Due to the microscopic size and sharpness of these fibers it's possible for them to penetrate the walls of the lung and enter the pleural cavity. As these fibers travel from the lung into the pleural cavity, the sharp strands shred and mutilate the mesothelium potentially destroying it and causing cancer.

As the asbestos fibers move into the pleural cavity, cancerous tumors can develop and this thickens the pleural fluid and harms proper lung movement. The tumors also may constrict the lungs and press on the ribcage or other organs resulting in terrible pain. Since the lungs are responsible for re-oxygenating the blood, cancerous cells can now spread into other parts of the body through the bloodstream.

It is still unclear by scientists and doctors why asbestos fibers cause the mesothelium to mutate into cancer. However, as more and more asbestos cases are reported, doctors are learning more about this devastating condition. Some believe that only one single fiber can create the events that cause mesothelioma. Despite the fact that there is no cure for mesothelioma, early diagnosis can help doctors give patients the opportunity to relieve a great deal of suffering and possibly prolong the patient's lives.