Peritoneal Mesothelioma Peritoneal Mesothelioma is a cancer that attacks the membrane called the peritoneum. This peritoneum surrounds the gastrointestinal system and lubricates the stomach and intestines. This lubrication enables the stomach and intestines to move so that they may function properly. Should the organs within the peritoneum not be able to move properly, a person will develop problems digesting and processing foods. A failure in the peritoneum may result in debilitating and painful symptoms. In many cases, the symptoms of Peritoneal Mesothelioma can be so subtle in the early stages that it is confused with numerous other, less dangerous conditions. Common symptoms of Peritoneal Mesothelioma may include: Stomach pain Abdominal pain Difficult bowel movements Weight lost Nausea Loss of appetite Weakness Abdominal swelling Causes of Peritoneal Mesothelioma As asbestos is ingested, its minute fibers begin to pass through the stomach lining. As these fibers pass through in quantity, the cells on the exterior lining of the stomach begin to mutate into malignant Mesothelioma cells. These cells accumulate into tumors, and eventually overcome the peritoneum, destroying healthy stomach cells in the process.