Tumors originating in the mesothelium can be benign or malignant. Benign tumors do not cause any damage and so will not hurt or do little harm to the individual since they are non-cancerous. On the other hand a malignant tumor of the mesothelium that contains cancerous cells is called malignant mesothelioma. Unfortunately tumors of the mesothelium are usually cancerous, and so malignant mesothelioma is usually just called "mesothelioma". There are mainly three types of mesothelioma that are Pleural Mesothelioma, Peritonial Mesothelioma and Pericardian Mesothelioma.
Pleural mesothelioma often originates within the chest cavity. It is a cancer of the lining of the lungs. This lining is called the pleura whose function is to produce lubricating fluid so that the lungs can move smoothly as the individual breaths. This form of mesothelioma has a high level of probability to metastasize (spread) to other organs of the body. Unfortunately it more usually does so than not. Pleural mesothelioma is the most common type of malignant mesothelioma with an occurrence of approximately 75% of all the malignant mesothelioma. Sometimes pleural mesothelioma is wrongly diagnosed as lung cancer. It is however different from lung cancer since lung cancer originates in the lungs while mesothelioma originates in the lining of the lungs.
Peritoneal Mesothelioma originates in the abdomen where it affects the peritoneum. The peritoneum is the lining of the abdominal cavity where it has the function to produce a lubricating fluid in order to allow the stomach to move freely. This type of mesotholioma usually spreads to other parts of the body such as the liver or bowel. It is however less common than pleural mesothelioma, amounting approximately from 10% to 20% of all malignant mesotheliomas. It is however more aggressive
Pericardial mesothelioma originates in the lining that surrounds the heart. This lining is called the pericardium, whose function is to produce a lubricating fluid that protects the heart so allowing the heart to move freely. This type of cancer is the less common type of malignant mesothelioma accounting for 5% to 15% of all types. This type of mesothelioma is very aggressive.