Mesotheloima is very rare form of cancer that affects the thin cell wall lining of body’s internal organs. This lining is called Mesothelium. Mesothelioma has three types’ pleural mesothelioma, pericardial mesothelioma and peritoneal mesothelioma. pleural mesothelioma affects the pleura, the lung lining. Peritoneal mesotheloima affects the peritoneal, in abdominal cavity wall. Pericardial mesotheloima affects lining of the heart, medically known as the pericardium.