Mesothelioma is extremely difficult to diagnose without prior knowledge of a patient’s potential risk. The first symptoms of the disease are non-specific pain or pressure in the chest and breathlessness and without a clue like a known history of asbestos exposure, it is difficult to quickly eliminate the many other disorders with similar presentation. Despite this, it is imperative to diagnose and treat suspected mesothelioma patients as quickly as possible. To do this doctors have developed a series of ever most specific tests and procedures to positively identify the presence of mesothelioma in the body. The first test that might indicate mesothelioma is an x-ray. Though it is unable to render specifics, an x-ray can show the build up of fluid in the pleural spaces that often indicates disease. A more specific imaging tool, a CT scanner, can help a talented diagnostician determine that the cause of the pleural effusion is indeed mesothelioma. This can be a challenging diagnosis because mesothelioma does not form discrete tumors. Instead it appears as a mass of tissue and cells covering the lungs and other affected organs like a sheath. This is due to its origins in the cells that line the membrane enclosing the lungs. From this point, the process shifts from raw diagnosis to proving the diagnosis and staging the cancer. For this, tissue biopsies are needed as well as further scanning using MRI and PET scans.