What is it all about? malignant Mesothelioma is an illness in which a slaughterous abnormal growth in animate being branch out on the mesothelium – the sac lining the centralized body cavities. The particular classification of mesothelioma is named for the large fibers of human body where the long illness begins. Pleural mesothelioma begins in the upper front of body, in the pleura that surrounds the terrestrial gastropods (outer lining of the terrestrial gastropods and internal front of body wall). It makes up about 70% of mesothelioma cases. Peritoneal mesothelioma begins in the lining of the abdominal cavity.