Mesothelioma is a form of cancer located in the lining of either the lungs, abdomen or the heart. These linings are thin layers of tissue covering the organ.

The pleura is the tissue covering the lungs and the wall of the chest cavity which cushions and protects the lungs. The peritoneum lines the abdominal wall and surrounds most of the organs in the abdomen. The pericardium is the tissue surrounding the heart.

Mesothelioma is a rare but very serious cancer. There are three types of mesothelioma based on the types of cancerous cells. The most common type is epithelioid and consists of 50-70% of total cases and has the best prognosis. The second type is called sarcomatoid, consists of 10-20 % of mesothelioma cases and is more unpredictable in nature. The third type of mesothelioma is called biphasic, it is a combination of the other two types and consists of 20-35% of all cases.

There are an estimated 2000-3000 new cases of mesothelioma in the United States every year. The majority of these cases begin in the chest wall (pleural mesothelioma), a few start in the abdomen (peritoneal mesothelioma) and very rare are the cases starting in the lining surrounding the heart (pericardial mesothelioma).

The pleura is a thin lining of mesothelial cells. There are two pleuras in the chest, the parietal pleura and the visceral pleura. The parietal pleura lines the chest wall including the inside of the ribs, diaphragm and pericardium. The visceral pleura covers the lungs and filters fluid to and from the chest. If the pleura becomes diseases it is not effective at eliminating fluid from the chest resulting in pleural effusion or too much fluid in the chest.

Mesothelioma is usually the result of exposure to asbestos. Most people who are diagnosed with mesothelioma have had jobs where they breathed asbestos fibers. It may take up to 60 years from the time of asbestos exposure until mesothelioma develops.

Although rare, mesothelioma is a serious form of cancer which is often in its advanced stage when a diagnosis is made. In general, prognosis for mesothelioma patient is poor, however, some patients live with the disease for a long time. As mentioned earlier, the type of mesothelioma has an impact on the prognosis, as well as, the age of the patient, how much tumor has developed and if treatment is rendered. There are many variables in evaluating a mesothelioma case, so only the patients doctor can determine the best treatment and possible prognosis on an individual basis.