What is Mesothelioma?

The definition of a malignant mesothelioma (pronounced me-zo-thee-le-O-muh) is a cancerous tumor of the mesothelium, the membrane that lines the interior of the chest and abdomen and surrounds the internal organs. It is a disease where malignant cancer cells are found in the sac lining the lungs in the chest (where the mesothelium is called the pleura) or abdomen (where it is called the peritoneum).

There are three main types of mesothelioma: pleural mesothelioma, peritoneal mesothelioma, and pericardial mesothelioma.

• Pleural mesothelioma - This is the most common form of mesothelioma. It is a cancer of the lining of the lungs called the pleura. The pleura, fibrous sheets that help protect the lungs, produces a lubricating fluid that allow the lungs to move smoothly as we breathe. Pleural mesothelioma is uncommon and may be misdiagnosed as lung cancer. Lung cancer, however, is different from pleural mesothelioma. Lung cancer is a malignant tumor that originates in the lungs; pleural mesothelioma occurs in the lining of the lungs. Approximately 75% of all malignant mesothelioma is pleural mesothelioma.
• Peritoneal mesothelioma - This cancer is much less common than pleural mesothelioma. It accounts for about 10 to 20% of mesotheliomas. Peritoneal mesothelioma is a cancer in the lining that surrounds the stomach or abdomen called the peritoneum. The peritoneum, cells that produce a lubricating fluid that protect the stomach, allows the stomach to move freely when food is digested. Peritoneal mesothelioma can start in the abdomen and spread to other parts of the body.
• Pericardial mesothelioma - This is the rarest form of mesothelioma - only about 5 to 15% of mesothelioma is pericardial mesothelioma. It is a cancer in the lining surrounding the heart called the pericardium. The pericardium, cells that produce a ubricating fluid that protects the heart, allows the heart to move freely when it is pumping blood to other parts of your body.