Mesothelioma is a type of cancer that is primarily caused by exposure to certain types of asbestos, a material once used in building construction. The disease can affect the lungs, the abdomen, or the heart. There are three types of mesothelioma:

• Pleural: Pleural mesothelioma affects the pleura - the lining of the lungs. It is the most common type of mesothelioma.
  
• Peritoneal: Peritoneal mesothelioma affects the peritoneum - the lining of the abdomen.
  
• Pericardial: Pericardial mesothelioma affects the pericardium, the membrane that surrounds the heart. It is the least common type, affecting about 5 percent of people with the disease.