星期五

Pericardial Mesothelioma

Pericardial Mesothelioma – affects the heartPericardial mesothelioma is the least frequent type of malignant mesothelioma. Only 5 to 15% of mesothelioma cases are pericardial mesothelioma.Pericardial mesothelioma is the least frequent type of malignant mesothelioma. Only 5 to 15% of mesothelioma cases are pericardial mesothelioma.
Pericardial mesothelioma affects the pericardium, a membrane structured by mesothelial cells that bound the heart and gives protection and support to this organ. The membrane consists of two disctinct layers - an outer layer called the parietal layer (called the heart sac or theca cordis), and an inner layer known as the visceral layer (called the epicardium). The parietal layer is part of a larger membrane that lines the entire chest cavity, while the visceral layer is the pericardial membrane that lines the heart.
It was already discovered long ago that pleural mesothelioma, which affects the lining of the lungs, is caused by inhalation of asbestos fibers. Nevertheless, doctors and scientists still cannot explain very well the way in which asbestos triggers the development of pericardial mesothelioma.
Some experts consider that inhaled asbestos fibers pass through via the bloodstream from the lungs to the heart. Nonetheless, there is no conclusive proof to support such theory.
What is discovered is that asbestos fibers somehow turn out to be lodged in the pericardial membranes that envelopes the heart. Once this happens, the body undergoes severe difficulty in removing the asbestos fibers and they are able to remain stuck in the membranes. Over a long interval of time, usually twenty years or even more, the asbestos fibers cause the cells of the pericardium to experience changes that can result in cancer.
When cells turn out to be cancerous they start to divide more quickly, without the control that orders the growth cycles of normal and healthy cells.When these malignant pericardial mesothelioma cells keep on growing, they develop to thicken the pericardial membranes, and finally cause tumors to grow. The alteration in this membrane is followed by the build-up of fluid between the pericardial layers, which combined with the layer thickening and eventually the heart gets pressured.

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