Mesothelioma is also grouped according to how the cells look under a microscope. There are 3 types
* Epithelial - between 5 and 6 out of 10 cases
* Sarcomatoid or fibrous - around 1 in 10 cases
* Mixed type (also called biphasic type) - between 3 and 4 out of 10 cases
These types of mesothelioma cells can be further divided into other types called
* Clear cell
* Small cell
* Acinar cell
* Tubopapillary cell
The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the extent of the cancer helps the doctors to decide on the best treatment. There are several staging systems for pleural mesothelioma.
Stage 1 The cancer cells are found in the pleura near the lung and heart or in the diaphragm or the lung.
Stage 2 The cancer has spread beyond the pleura to lymph nodes in the chest.
Stage 3 The cancer has spread into one or more of the chest wall, the centre of the chest, the heart, the diaphragm, the abdominal lining, and the nearby lymph nodes.
Stage 4 The cancer has spread to distant organs or tissues.
A staging system has not yet been established for peritoneal mesothelioma. But sometimes doctors may use the TNM staging system for this cancer. The initials T, N and M stand for 'tumour', 'nodes' and 'metastases'.