Types and grades of mesothelioma

Where mesothelioma can start

The type of mesothelioma describes what type of cell the cancer started in, and where it is in your body.

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.

It is rare, but you can get mesothelioma in the outer lining of other organs such as the:

• heart (pericardial mesothelioma)

• testes (testicular mesothelioma)

Mesothelioma by cell type

Mesothelioma is also grouped according to how the cells look under a microscope. The different types include:

• epithelioid – the most common type

• sarcomatoid

• biphasic - this has a mix of epithelioid and sarcomatoid cells

Knowing the type of cell that is affected may give your doctors more information about how the mesothelioma might respond to treatment.

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

Find out about the stages of mesothelioma