• pleural mesothelioma
   
• peritoneal mesothelioma

Pleural mesothelioma starts in the tissues (pleural membranes) covering the outside of the lungs. It is the most common type. Between eight and nine out of every 10 cases of mesothelioma are pleural. The rest are peritoneal.

Peritoneal mesothelioma starts in the tissue lining the inside of the abdomen (stomach).

Mesothelioma gets its name from the part of the body where the cancer starts, in the mesothelium. The mesothelium is the name for the membrane that covers and protects most of the internal organs of the body. This includes the heart and the abdomen, as well as the lungs. It is made of two layers with a small space between. One layer surrounds the organ, the other makes a sac around it. The mesothelium makes fluid between the two layers that lubricates the movement of the organs it protects.

When the normal cells of the mesothelium get out of control, multiply and spread, mesothelioma occurs. These abnormal cells clump together to form a cancerous or malignant tumour. This is called primary cancer.