Mesothelioma is an inflammation of the mesothelium caused by prolonged exposure to asbestos fibers. These fibers get into the body through inhalation and orally and get stuck in the lining of the lungs where they cause inflammation of the pleura resulting in accumulation of fluids between the tissues. Inhaled asbestos fibers are the principal cause of pleural mesothelioma while the one that goes into the body orally is the chief cause of peritoneal mesothelioma.