What is malignant mesothelioma?

Malignant mesothelioma is a rare type of cancer caused by asbestos exposure.  Malignant mesothelioma affects the mesothelial tissue of three large body cavities:  the pleura (lung cavity), the peritoneum (abdominal cavity) and the pericardium (heart sac).  The three types of malignant mesothelioma are pleural mesothelioma, peritoneal mesothelioma and pericardial mesothelioma.