WHAT IS MESOTHELIOMA ?

Mesothelioma is a rare form of cancer in which malignant (cancerous) cells are found in the mesothelium, a protective sac that covers most of the body's internal organs. This is a disease in which cells of the mesothelium become abnormal and divide without control or order. They can invade and damage nearby tissues and organs. Cancer cells can also metastasize (spread) from their original site to other parts of the body. Mesothelioma develops in the lining around the lungs (the “pleura”), abdomen (the “peritoneum”), or heart (the “pericardium”).
Mesothelioma is almost always caused by exposure to asbestos. Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles.

When asbestos particles are inhaled or swallowed, they bypass the body’s natural defense systems, lodging themselves in the lungs and abdomen. The sharp, microscopic asbestos fibers eventually make their way to the outer edge of the chest and abdominal cavities and into a membrane called the mesothelium. The mesothelium, a double-layered protective membrane, surrounds all the organs of the human body and is vital to their proper function. The mesothelium keeps the organs in place while simultaneously lubricating them, allowing them to flex and move with breathing and other movement. Asbestos fibers cause lesions and scarring on the mesothelium, ultimately leading to the formation of tumors. The damaged cells secrete large amounts of a clear fluid that presses on the lungs and other organs, causing severe discomfort. In addition to these fluid secretions, aggressive tumor growth in later stages can lead to the rapid spread of cancer throughout the chest and abdomen, as well as cardiac or respiratory failure. Mesothelioma progresses extremely slowly. The cancer may take anywhere from 25 to 50 years to show symptoms. Often, when a victim is diagnosed with mesothelioma, the disease has already reached an advanced stage and permanent damage has already occurred. Although this cancer can appear in men and women at any age, it occurs more often in men and risk increases with age. Mesothelioma is still somewhat a rare cancer, rates have increased over the last 20 years.

What is the mesothelium?

The mesothelium is a membrane that covers and protects internal organs. The mesothelium allows moving organs to glide easily against adjacent structures. It is composed of two layers of cells: One layer immediately surrounds the organ; the other forms a sac around it. The mesothelium produces a lubricating fluid that is released between these layers, allowing moving organs (such as the beating heart and the expanding and contracting lungs). The mesothelium has different names, depending on its location in the body. The peritoneum is the mesothelial tissue that covers most of the organs in the abdominal cavity. The pleura is the membrane that surrounds the lungs and lines the wall of the chest cavity. The pericardium covers and protects the heart. The mesothelial tissue surrounding the male internal reproductive organs and the tunica serosa uteri covers the female internal reproductive organs.