Types and grades of mesothelioma

The type of mesothelioma describes what type of cell the cancer started in, and where it is in your body. The grade of a cancer tells you how much the cancer cells look like normal cells.

Knowing what type and grade of mesothelioma you have helps your doctor decide which treatment you need. 

Where you can get mesothelioma

There are 2 main types of mesothelioma. These are mesothelioma in the:

• covering of the lung (pleural mesothelioma)
• lining of the tummy (peritoneal mesothelioma)

​Pleural mesothelioma starts in the sheets of tissue that cover the lungs. These are called the pleura. Peritoneal mesothelioma grows in the tissue lining the inside of the tummy (abdomen). This is called the peritoneum.

Pleural mesothelioma is much more common than peritoneal mesothelioma.

Rarely, you can also get mesothelioma in other places such as the lining of the heart (pericardium).

Mesothelioma by cell type

Mesothelioma is also grouped according to how the cells look under a microscope. These are 3 main types:

• epithelioid – the most common type
• biphasic
• sarcomatoid

Grades

The grade of a cancer tells you how much the cancer cells look like normal cells. The grade gives your doctor an idea of how the cancer might behave and what treatment you need.

There are 2 grades for the most common type of mesothelioma (epithelioid):

• low grade
• high grade