Peritoneal mesothelioma is a malignant mesothelioma that forms in the peritoneum, the portion of the mesothelium that surrounds the stomach and the intestines in the abdominal cavity.Mesothelioma of the abdomen, 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.The principal question is how the asbestos fibers are getting into the peritoneum, since it is not connected directly to the lungs.
Some researchers believe that peritoneal mesothelioma is caused when asbestos fibers are ingested in water or (more rarely) food, and then migrate through the stomach or intestinal wall. Other researchers believe that the asbestos fibers must be coming in through the lungs and then migrating into the peritoneum via the lymph system or the bloodstream. It is even possible that asbestos fibers might be present in sputum which is coughed up and then ingested.
A patient with peritoneal mesothelioma may not demonstrate symptoms of the cancer for 20 to 50 years after initial asbestos exposure since it often takes years for mesothelioma to manifest. In the case of peritoneal mesothelioma, asbestos fibers travel into the peritoneal layers where they cause irritation and inflammation and the development of cancerous cells which divide and grow uncontrollably. The cells cause thickening of the peritoneum and fluid build-up in the peritoneal layers. As the cancerous cells continue to divide overtime, tumors start to form. Most peritoneal mesothelioma symptoms are caused by this membrane thickening, fluid build-up, and eventual tumor development, all of which put pressure on internal organs.
There is an extremely rare form of peritoneal mesothelioma in which the testicles of a male patient develop tumors. The covering of the scrotum is actually an outgrowth of the peritoneal mesothelium. It is believed that fibers from the stomach may migrate to the scrotal covering and that a typical mesothelioma can form there. This is exceptionally rare, however.