Malignant mesothelioma is a relatively rare type of cancer that only develops in people who have experienced long-term or repeated exposure to asbestos. In America, peritoneal mesothelioma cases account for approximately 25% of the 2,000 to 3,000 reported cases of mesothelioma each year
Peritoneal mesothelioma develops in the abdomen, in the mesothelial cells that form the peritoneum. The peritoneum is a membranous layer that is made up of two sub-layers —the parietal layer and the visceral layer. The parietal layer covers the abdominal cavity, while the visceral layer surrounds abdominal organs. Together, these two layers provide support and protection for abdominal organs and the abdominal cavity as a whole.
How Does Asbestos Cause Peritoneal Mesothelioma?
There are two main theories regarding the method by which asbestos exposure leads to the development of peritoneal mesothelioma:
• Asbestos fibers are ingested, and these fibers work their way from digestive organs into the
membrane via the lymphatic system.
Regardless of how asbestos fibers actually enter the peritoneal layers, once they do enter the membrane, the body is unable to expel them. The fibers become trapped in the peritoneal membrane, and over a period of two or more decades, they cause certain changes in the mesothelial cells of the peritoneum.
The exact way in which asbestos fibers cause changes in these mesothelial cells is uncertain. One theory is that asbestos fibers provoke long-term inflammation and irritation that eventually causes mesothelial cells to become cancerous. When cells become cancerous, they lose the ability to regulate their own division and growth.
Cancerous mesothelial cells divide and grow without restraint; this uncontrolled cell growth causes thickening of the peritoneum and the build-up of fluid in the peritoneal layers. Over time, as cancerous cells continue to divide, tumors form.
Symptoms of Peritoneal Mesothelioma
Most peritoneal mesothelioma symptoms are caused by membrane thickening, fluid build-up, and eventual tumor development, all of which put pressure on internal organs.
Symptoms of peritoneal mesothelioma include:
• Abdominal pain or swelling
• Changes in bowel habits (such as diarrhea or constipation)
• Development of lumps under the skin on the abdomen
• Night sweats or fever
• Unexplained weight loss
• Nausea or vomiting