is a rare form of cancer in which malignant (cancerous) cells
are found in the mesothelium,
sac that covers
most of the body's internal organs. Most people who develop mesothelioma
have worked on jobs where they inhaled asbestos particles.
Mesothelioma (cancer of the mesothelium) 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. Most cases of mesothelioma begin
in the pleura or peritoneum.
The Mesothelium Explained
The mesothelium is a membrane that covers and protects most of
the internal organs of the body. 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) to glide easily against adjacent structures.
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 is called
the tunica vaginalis testis. The tunica serosa uteri covers the
internal reproductive organs in women.
Mesothelioma is Rare
Although reported incidence rates have increased in the past 20
years, mesothelioma is still a relatively rare cancer. About
2,000 new cases of mesothelioma are diagnosed in the United States
each year. Mesothelioma occurs more often in men than in women
and risk increases with age, but this disease can appear in either
men or women at any age.
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