People exposed to asbestos for long years are prone to mesothelioma, a type of cancer that affects the membrane that covers and protects the internal body organs. Mesothelium is the membrane that protects almost all internal organs of the body. There are two layers in mesothelium, one covering the immediate surface and the other forms as a sac. Diagnosing mesothelioma begins with evaluating the patient’s medical history and in general mesothelioma prognosis is very difficult. People who are suspected for mesothelioma are asked to undergo complete physical examination including X rays of the chest and abdomen and lung function tests. Any type of mesothelioma including pleural mesothelioma is diagnosed and confirmed only by biopsy. A MRI scan or a CT scan is also necessary in some cases to know the intensity of the disease.