MesotheliomaWhat is Mesothelioma?
Diagnosis of Mesothelioma
If you suspect you may have a mesothelioma, the doctor can determine if you have the disease using a series of diagnostic tests.
Medical History and Physical Exam:
Before any tests are run, a complete medical history will be taken to check for risk factors and symptoms. This will include questions to determine when and how you have been exposed to asbestos.
Then, a physical exam will provide information about any symptoms of mesothelioma and other health related problems. Patients with pleural mesothelioma oftentimes suffer from a painful recurring cough, whereas patients with pericardial and peritoneal (heart and abdominal) mesothelioma often have fluid build-up, known as ascites if it is on the abdomen, or effusion if it is one the heart.
Imaging Tests:
Chest X-rays are usually the first diagnostic tests because they are non-invasive. X-Rays may show irregular thickening of the pleura, pleural calcifications or mineral deposits on the lungs, and fluid in the pleura. These symptoms often point to mesothelioma.
Imaging studies such as x-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans can determine the location, size, and extent of the cancer, which will then help patients to decide upon the plan of treatment.
CT scans create a series of pictures of the body using many different angles. Computerized technology uses every photo taken of the cross-sections of the body and combines them, giving a three dimensional image. Many times patients will have a harmless dye injected into their veins in order to highlight the CT scans findings.
MRI scans use magnetic fields, like the CT scan to create detailed, cross-sectional images of selected parts of the body.
Fluid and Tissue Samples:
Oftentimes, a sample pleural, pericardial or peritoneal fluid can be removed and tested by inserting a needle into the chest cavity. This fluid is then tested to show if cancerous cells are present and to determine its chemical makeup.
Likewise, a sample of a pleural or pericardial tumor can be obtained using a relatively new technique called thoracoscopy. A thoracoscope is a telescope-like instrument that is connected to a video camera. In order to collect tissue, the thoracoscope is inserted through a small chest incision. The doctor can then view the tumor and use special forceps on the thoracoscope to collect tissue. The tissue is then removed and tested for cancerous cells. Additionally, fluid can also be removed during a thoracoscopy.
Surgery allows doctors to remove a larger sample of tumor or, sometimes, to remove the entire tumor. This is done either by thoracotomy or a laparotomy which open the chest and abdominal cavities, respectively.
Bronchoscopy is another procedure used to diagnose pleural mesothelioma. A flexible lighted tube is inserted through the mouth, down the trachea, and into the bronchi, where doctors can determine if there are other masses in the airway. Tissues can then be collected and tested.
Finally, mediastinoscopy uses a lighted tube that is inserted under the sternum (chest bone) at the level of the neck and moved down into the chest. This procedure allows the surgeon to view the lymph nodes in this area and remove samples to test for cancer. Tests of lymph nodes can give the doctor an idea as to if the cancer is still localized or if it has started to metastasize, or spread, to other regions of the body.
The diagnosis of mesothelioma presents problems primarily initially in the distinction between mesothelioma and other forms of cancer such as adenocarcinoma or benign, noncancerous pleural inflammation. The best diagnostic tool at the moment remains the open pleural biopsy performed during thoracoscopy. This procedure also allows for direct visualization of the inside of the chest and provides information of involvment of other organs and extension of disease. Other procedures with lower yields are CT guided pleural biopsy, or blind pleural biopsy. In addition to the appearance of the tumor, pathologists often rely on a panel of histochemical and immunohistochemical stains to diagnose or exclude meosothelioma. Currently markers linked to prognosis of mesothelioma are under study, but have not been validated yet for the general use.
