Mesothelioma can be categorized generally into two types according to the type of cancerous cells. These are malignant mesothelioma and benign mesothelioma. The former is the more dangerous one as it spreads to other body parts while the latter one is a non cancerous condition.
Malignant mesothelioma is further classified into four types on the basis of the site of cancer. As the major cause of mesothelioma is asbestos exposure, once asbestos enters the body it can affect different organs including the throat, lungs, stomach, heart and testicles. Thus the main types of malignant mesothelioma are:
1) Pleural mesothelioma
This type of mesothelioma arises in the lung pleura, where the mesothelial lining of the lungs are affected. It is the most common type of mesothelioma that people suffer from. It comprises of up to 75 per cent cases that are diagnosed as mesothelioma.
2) Peritoneal mesothelioma
It is the second most common type of mesothelioma which totals 20 per cent of the mesothelioma cases. The asbestos affects the mesothelial lining of the peritoneal or the abdominal cavity and causes cancer cells to develop here.
3) Pericardial mesothelioma
This type of mesothelioma affects 5% of all the mesothelioma patients. The pericardial lining of the heart called the pericardium is affected by the asbestos and develops cancer.
4) Testicular mesothelioma
The site of cancer is the tunica vaginalis of the testicles and is the least common type of mesothelioma. This is a rare mesothelioma which only affects the male population.
The types of malignant tumor or cancer cells involved in the development of mesothelioma are of three main types namely Epithelioid, Sarcomatoid and Mixed or biphasic cells.
The epitheliod is the most common one accounting for 50 to 70 percent cases but have the best possibility of survival. The affected areas include the covering surrounding the internal organs and internal surfaces in the body.
The other type is Sarcomatoid which is much more serious than the epitheliod, and it affects the secondary tissues including the bone, muscles, cartilage or fat. This type of cancer cell is a much more rare type that occurs in 7-20% of the cases.
Mixed/biphasic refers to both types of cancers that occurs simultaneously, and making up the rest of the 20-35% of the mesothelioma cases that are reported.
This type of mesothelioma is the non cancerous form of the mesothelioma and is rare. Recently it was referred to as the “solitary fibrous tumor.” It is not a cancer itself but can develop into cancerous forms.
The benign mesothelioma can occur in the pleura or the peritoneum. This usually starts in the sub mesothelium layer that lies beneath the mesothelium of either the pleura or the peritoneum.