Deep Discussions About Pleural Mesothelioma

Pleural mesothelioma develops in the lining of the lungs. This lining is called the pleura, or pleural membrane, and it is made up of mesothelial cells. This pleural membrane consists of two layers - the parietal layer, and the visceral layer. The parietal layer is an outer layer that lines the entire chest cavity and diaphragm, while the visceral layer is an inner layer that covers the lungs. Together, these two layers provide support and protection for the lungs and the chest cavity.

In cases of pleural mesothelioma, asbestos exposure occurs via inhalation of asbestos fibers. Once these fibers have entered the lungs, they work their way to the pleural membrane, and the body experiences great difficulty in expelling these fibers. Over a long period of time - typically two decades or more - asbestos fibers cause changes in these pleural cells, which may cause scarring of the lungs and, eventually, the formation of tumors.

When pleural cells become cancerous, they are no longer regulated by the mechanisms that control division of normal healthy cells. They begin to divide continuously, and this causes thickening of pleural membranes. As a result, lung capacity is reduced, and fluid begins to build up between pleural layers.

Medical experts have been unable to definitively assess the prognosis of pleural mesothelioma partly because there are relatively few cases and it is so difficult to diagnose that patients don't get treatment for a long time after the disease strikes. Studies of pleural mesothelioma patients show that important prognostic factors include stage of cancer, age, and histology. Surgery improves the lifespan of the patient, even though it does not cure the disease. For patients treated with surgery, factors associated with improved long-term survival include epithelial histology, negative lymph nodes, and negative surgical margins. Nodal status is an important prognostic factor. Studies have shown the median survival of patients with malignant pleural disease is 16 months.

Pleural effusions and peritoneal effusions are experienced by two-thirds of patients. Hemothorax - the collection of blood in the pleural cavity - also is a symptom. A pleural smear examines a sample of pleural fluid under the microscope to detect for abnormal organisms. The test is performed when infection of the pleural space is suspected or when an abnormal collection of pleural fluid is noticed by chest X-ray. Sometimes the tumor grows through the diaphragm, making the site of origin difficult to assess.