What is mesothelial tissue?
The mesothelium is a sac made up of protective mesothelial cells that cover most internal organs in the body. This protective covering is composed of two layers; one layer of outer cells that covers the organ and an inner layer that forms a protective sac around it. The mesothelium produces and secretes a lubricating fluid between these layers. This reduces friction between the organs and allows moving organs (e.g., the lungs) to slide easily. This particular area around the lungs is called the pleural space. Besides lungs, mesothelial tissue is also found lining the abdominal organs, such as testes and heart.
What is mesothelioma?
Mesothelioma is a cancer of mesothelial cells or tissues that occurs when they start growing out of control. It also causes the cells to lose their ability to produce the lubricating fluid. This results in the reduction of gliding movement, unwanted encasement of organs, and accumulation of excess fluid buildup – ultimately causing symptoms. During the later stages, these cells can grow and spread to other areas of the body. This advanced stage of any cancer is called metastasis.
Most of the mesotheliomas (approximately 80%) develop in the lining of the lung. About 20% is found in the peritoneum (abdominal cavity lining), and even more rarely (less than 1) mesothelioma is found in the lining of the testicles or heart.
Due to its extended latency period – the time between exposure to risk factors and the development of the symptoms – mesothelioma often occurs in older people and usually diagnosed at an advanced stage. All types of mesotheliomas are more common in men, especially in those who served in the armed forces or worked in the construction and automotive industries. First responders, such as paramedics, firefighters, police officers, and EMTs, are also at a higher risk for developing mesothelial cancers. Typically, these professions got exposed to higher levels of contaminants and environmental toxins through the mouth or nose and causing cancer.
There are four types of mesothelioma cancer that are defined by the location of tumors in the body organs. The most common forms of mesothelioma are pleural and peritoneal cancer. Pericardial mesothelioma is rare and accounts for less than 1% of cases.
The prognosis, signs and treatment options differ by type of mesothelioma.
Pleural Mesothelioma (Lungs)
Pleural mesothelioma occurs in the lung linings, known as the pleura. It’s the most common type of aggressive disease. About 80% of all cases of mesothelioma diagnosed are pleural.
Peritoneal Mesothelioma (Abdomen)
This type is the second most common form of mesothelioma cancer. It is diagnosed in approximately 15-20% of all cases. This form of mesothelioma has an impact on the lining of the peritoneum (abdominal cavity).
Pericardial Mesothelioma (Heart)
Pericardial mesothelioma is formed in the pericardium (the lining of the heart). It is a very rare cancer. Fewer than 100 people are diagnosed with pericardial mesothelioma per year in the United States. This type of disease accounts for less than 1% of the total number of diagnosed cases of mesothelioma.
Testicular mesothelioma is found in the tunica vaginalis (the lining of the testicles) and is rarest of all the mesothelioma cancers.