Two types of Mesothelioma

• Pleural mesothelioma 
• Peritoneal mesothelioma

The pleural type grows in the tissues covering the lungs. The peritoneal type grows in the tissue lining the inside of the abdomen (tummy). Pleural mesothelioma is much more common than peritoneal mesothelioma.

Between 70% - 80% of cases are pleural mesothelioma. Peritoneal mesothelioma is much less common, making up between 10% - 20%.

Cell types
Mesothelioma is also grouped according to how the cells look under a microscope. When mesothelioma is grouped this way, there are 3 types
• Epitheloid 
• Sarcomatoid or fibrous 
• Mixed type (also called Biphasic type)
Between 50%-70% of mesothelioma diagnosed are the epitheloid type.

Between 7% – 20% of mesothelioma diagnosed are sarcomatoid type.

Between 20% – 35% of mesothelioma diagnosed are mixed and have both epitheloid and sarcomatoid cells.

These types of mesothelioma cells can further divide into other types of cancerous cells called
• Clear cell 
• Small cell 
• Acinar cell 
• Tubopapillary cell

With so many different types of cells capable of developing into mesothelioma, it makes it very difficult to diagnose this disease.