Pleura (definition of)

Pleura (from the Greek word pleurón, meaning "rib," or "side") is that part of the mesothelium surrounding the lungs. It consists of two layers; an outer one attached to the chest wall known as the parietal pleura, and an inner one, properly identified as the visceral pleura. This latter layer attached to the lungs themselves. The space between these layers contains a lubricative fluid produced by the lymphatic system.

Mesothelioma is the name of the form of cancer that attacks these layers. Researchers are not entirely certain how asbestos fibers cause normal cells to become malignant, but evidence thus far suggests that mesothelioma results from the convergence of several elements that may include other toxins, genetic predisposition to cancer and a virus known as SV40. Asbestos seem to behave as a catalyst, causing cellular mutations at the DNA level and causing the cells to become malignant.

As the malignancy spreads across the lung surfaces and lymphatic fluid builds up, the lungs themselves become constricted. Ironically, it is not the cancer directly that kills the patient; it is the fact that the patient suffers slow suffocation.

Mesothelioma has a strong tendency to metastasize into other areas of the body; including the mesothelial linings of the heart and abdomen (see pericardium and peritoneum).