Types of Mesothelioma

Pleural mesothelioma:
Pleural mesothelioma is the most common type of mesothelioma, a rare cancer that develops in the mesothelial cells that make up the mesothelium, a membrane that lines many of the body’s organs and cavities. In the case of pleural mesothelioma, the cancer develops in the lining of the lungs, called the pleura or pleural membrane

The pleura is comprised of two layers which provide support and protection for the lungs and chest cavity. The outer layer, or the parietal layer, lines the entire chest cavity and the diaphragm. The inner layer, or visceral layer, covers the lungs. Pleural mesothelioma typically develops in one layer, but can metastasize, or spread, to the other layer.

Like all mesothelioma cancers, pleural mesothelioma is caused by asbestos exposure and develops when the toxic asbestos fibers become trapped in the spaces between the mesothelial cells.

Peritonial Mesothelioma:
Peritonial mesothelioma is a rare, aggressive cancer caused by asbestos exposure. Of the 2,000 to 3,000 cases of mesothelioma diagnosed in the United States annually, 10 to 20 percent of the patients are diagnosed with peritoneal mesothelioma. Peritoneal mesothelioma develops in the abdomen, in the mesothelial cells that form a membranous layer called the peritoneum.

The peritoneum is a membranous layer that is made up of two ’sub-layers’ called the parietal and visceral layers. 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.

Peritoneal mesothelioma, like all types of mesothelioma, is caused by asbestos exposure. Though it can take many years for a patient to demonstrate symptoms of peritoneal mesothelioma, the cancer develops when the asbestos fibers become lodged in the spaces between the mesothelial cells.

Pericardial mesothelioma:
Pericardial mesothelioma accounts for approximately half of all pericardial tumors and is an extremely rare. Researchers from various mesothelioma studies report that pericardial mesothelioma accounts for approximately 1 to 6 percent of all mesotheliomas. To date, fewer than 150 cases have been presented in medical literature and approximately 200 cases have been reported worldwide. Pericardial tumors are typically diffuse (not localized) and tend to cover most of the heart.

Pericardial mesothelioma develops in the pericardium, a membrane made up of mesothelial cells that surrounds the heart and provides protection and support to this organ. The membrane is composed of two different 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.