Pleural Mesothelioma Description

Pleural mesothelioma is the mesothelima that deals with the lungs. Two types exist:

• Malignant (cancerous)
• Benign (not)

Benign mesothelioma can often be removed surgically, are generally not life-threatening, and are not usually related to asbestos exposure.

Pleural mesothelioma can occur because of a long-term exposure to Asbestos. "Asbestos" refers to a family of magnesium-silicate mineral fibers that have been commonly used for insulation and in the shipbuilding and construction industries. Interestingly, a history of asbestos exposure is found in 80 percent of patients who present with mesothelioma.

Other factors that may contribute towards pleural mesothelioma include:

• chronic lung infections
• tuberculous pleuritis
• radiation (Thorotrast)
• exposure to the simian virus 40 (SV40) or mineral fibers (Zeolite).

Although tobacco smoking has not been associated with the development of mesotheliomas, the combination of smoking and asbestos exposure greatly increases the risk of lung cancer.

The condition itself is a cancer of the cells that make up the pleura or lining around the outside of the lungs and inside of the ribs. Its only known cause in the U.S. is previous exposure to asbestos fibers, including chrysotile, amosite or crocidolite. This exposure is likely to have happened twenty or more years before the disease becomes evident, since it takes many years for the disease to "incubate." It is the most common type of mesothelioma, accounting for about 75% of all cases.

The first step in verifying pleural mesothelioma usually is a chest x-ray or CT scan. The next step is a bronchoscopy - this involves a viewing scope which the doctors use to look inside the lungs.

The actual diagnosis itself usually requires removing and analyzing a piece of tissue through a biopsy. This could be a needle biopsy, an open biopsy, or through a tube with a camera (thoracoscopy or chest scope.) The tissue sample is tested by a pathologist.

Fluid build-up from the pleural effusion can generally be seen on a chest x-ray and heard during a physical examination. This is important because there are also benign pleural effusions and other tumors that have a similar appearance to mesothelioma such as pneumonia.

The spread of the tumor over the lung pleura will thicken it, reducing the flexibility of the pleura and encasing the lungs in an increasingly restrictive space. This makes breathing more difficult. At first a person with mesothelioma may be breathless only when he or she exercises, but as lung function drops, he or she can become short of breath even while resting.

The tumor spreads by direct invasion of surrounding tissue. As it spreads inward it can compress the lungs. As the tumor spreads outward it can invade the chest wall and ribs, and this can be extremely painful.

Currently we do not know exactly how and why asbestos fibers cause mesothelial cells to become abnormal (malignant or cancerous.) Many clinical studies are dedicated to this.

As of yet, there is no known cure for malignant mesothelioma. The prognosis depends on various factors, including the size and stage of the tumor, the extent of the tumor, the cell type, and whether or not the tumor responds to treatment.