Mesothelioma Information

What is Mesothelioma? 

There are spaces, called cavities or sacs, in the body that hold different internal organs. For example, the lungs sit in the pleural cavity, the stomach in the peritoneal cavity and the heart in the pericardium sac. All of these cavities are lined with a membrane called the mesothelium. This thin lining produces fluids that lubricate the space between the organ and the cavity wall, which allows for movement during processes like breathing, when the lungs fill up with air. Mesothelioma is a cancer that affects these linings.

Types of Mesothelioma

The various types of mesothelioma are often named for the cavity that it develops in. When cancer develops in:

• The outer lining of the lungs and internal chest wall, it is called pleural mesothelioma.
• The lining of the abdominal cavity, it is called peritoneal mesothelioma.
• The space surrounding the heart, it is called pericardial mesothelioma.
• The lining that surrounds the testicles, it is called testicular mesothelioma.

The most common mesothelioma type is pleural mesothelioma, which accounts for approximately three out of every four cases. Both pericardial mesothelioma and testicular mesothelioma are extremely rare forms of the disease.

Subtypes of Mesothelioma 

There are three sub-classifications of mesothelioma based on the way the cells look under a microscope:

• Epithelioid
• Sarcomatoid (fibrous)
• Mixed (biphasic)

The majority of mesotheliomas are epithelioid. These tend to have a better prognosis than the other mesothelioma types. Sarcomatoids are the least common of the three types, accounting for only 10 to 20 percent of all cases. The mixed (biphasic) type of mesothelioma has both epithelioid and sarcomatoid characteristics and accounts for approximately 30 percent of all cases.

Mesothelioma Incidence

Mesothelioma is a rare disease. Approximately 2,500 people, mostly over the age of 65, were diagnosed with mesothelioma in the United States in 2009.

Mesothelioma is strongly associated with exposure to asbestos, a fibrous mineral used in construction materials for many years. People who have been exposed to asbestos may have inhaled tiny fibers that can remain in the lungs for 20 to 50 years. During this lengthy period of time, mesothelioma may slowly develop.

Next Topic: Mesothelioma Risk Factors