Mesothelioma (or more precisely malignant mesothelioma) is a rare form of cancer that develops from stem cells transformed into misothiliom, the protective lining that covers many of the internal organs of the body. Is usually caused by exposure to asbestos.
The most common anatomical location for developing mesothelioma is the pleura (outer lining of the lungs and internal chest wall), but can also arise in the peritoneum (the lining of the abdominal cavity), myopericarditis in (the SAC that surrounds the heart) or tunica vaginalis (testicular SAC that surrounds).