Mesothelioma
Malignant mesothelioma is an uncommon, but no longer rare,
cancer that is difficult to diagnose and poorly responsive to
therapy. Malignant mesothelioma is the most serious of all
asbestos-related diseases. A layer of specialized cells called
mesothelial cells lines the chest cavity, abdominal cavity, and
the cavity around the heart. These cells also cover the outer
surface of most internal organs. The tissue formed by these
cells is called mesothelium.
The mesothelium helps protect the organs by producing a special
lubricating fluid that allows organs to move around. For
example, this fluid makes it easier for the lungs to move inside
the chest during breathing. The mesothelium of the chest is
called the pleura and the mesothelium of the abdomen is known as
the peritoneum. The mesothelium of the pericardial cavity (the
"sac-like" space around the heart) is called the pericardium
Tumors of the mesothelium can be benign (noncancerous) or
malignant (cancerous). A malignant tumor of the mesothelium is
called a malignant mesothelioma. Because most mesothelial tumors
are cancerous, malignant mesothelioma is often simply called
mesothelioma. Mesothelioma was recognized as a tumor of the
pleura, peritoneum and pericardium in the late 1700's. However
it was not until much later, in 1960, that this particular type
of tumor was described in more detail and even more importantly,
its association with asbestos exposure was recognized. The first
report linking mesothelioma to asbestos exposure was written by
J.C.Wagner, and described 32 cases of workers in the "Asbestos
Hills" in South Africa. Since than the relationship between
mesothelioma and asbestos exposure has been confirmed in studies
around the world.
The incidence of mesothelioma in the United States remains very
low, with 14 cases occurring per million people per year.
Despite these numbers the noticed threefold increase in
mesothelioma in males between 1970 and 1984, is directly
associated with environmental and occupational exposure to
asbestos, mostly in areas of asbestos product plants and
shipbuilding facilities. Although the disease is much more
commonly seen in 60-year old men, it has been described in women
and early childhood as well. The cause of the disease is not so
well understood in these latter two groups, but there is some
evidence of possible asbestos exposure for some of these cases
as well
Mesothelioma is one of the deadliest diseases known to man; the
average life span of an inflicted person from the time of
diagnosis until death is less than 24 months. It's a disease
that strikes approximately 3,000 United States citizens each and
every year; hard working people who have labored for a lifetime
to provide for their families, doing the work that keeps this
country running and a great place to live. They worked in
factories, at shipyards, in mines, for the US military, as
engineers, as pipefitters, as steel workers, as auto mechanics,
and in so many other professions. They came home to their loved
ones exhausted and covered in dirt and dust; tired, but content
that they had a job and were providing for their family. Content
that they were putting food on the table and a house over their
loved one's heads. Content that they were working to make a
better life for their families in this generation and the
next... But what they didn't know was that while they were
working so hard, they were not only slowly killing themselves,
but those that they were working so hard to help; their family,
their loved ones.
What is the mesothelium? 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
What Is My Diagnosis? There are three types of mesothelioma.
Pleural mesothelioma is a cancer of the lining of the lung
(pleura), peritoneal mesothelioma is a cancer of the lining of
the abdominal cavity (peritoneum), and pericardial mesothelioma
is a cancer of the lining surrounding the heart (pericardium).
Sub-types (or cell types) of mesothelioma are epithelioid (the
most common, and considered the most amenable to treatment),
sarcomatous (a much more aggressive form), and biphasic or mixed
(a combination of both of the other cell types). The structural
appearance of cells under the microscope determine the cell or
sub-type of mesothelioma. Epithelioid is the least aggressive;
sarcomatoid, the most aggressive. The biphasic or mixed cell
type shows structural elements of both of the other two.