Mesothelioma often goes undiagnosed until it is in an advanced stage. The diagnosis is difficult because the symptoms are similar to those of a number of other conditions, such as pneumonia and severe emphysema. Sometimes it is hard to tell the difference between malignant mesothelioma and lung cancer. The following tests and procedures may be used to diagnose mesothelioma:
Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits, exposure to asbestos, past illnesses and treatments will also be taken.
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. Asbestosis is often diagnosed by x-ray and tumors are visible.
Biopsy: The removal of cells or tissues from the pleura or peritoneum so they can be viewed under a microscope by a pathologist to check for signs of mesothelioma. Procedures used to collect the cells or tissues include the following:
Fine-needle (FNA) aspiration biopsy of the suspected mesothelioma tumor in the lung lung: The removal of tissue or fluid using a thin needle. An imaging procedure is used to locate the suspected mesothelioma tumor or fluid in the lung. A small incision may be made in the skin where the biopsy needle is inserted into the suspected mesothelioma tumor or fluid, and a sample is removed.
Thoracoscopy: An incision (cut) is made between two ribs and a thoracoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted into the chest.
Peritoneoscopy: An incision (cut) is made in the abdominal wall and a peritoneoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted into the abdomen.
Laparotomy: An incision (cut) is made in the wall of the abdomen to check the inside of the abdomen for signs of disease.
Thoracotomy: An incision (cut) is made between two ribs to check inside the chest for signs of disease.
Bronchoscopy: A procedure to look inside the trachea and large airways in the lung for abnormal areas. A bronchoscope is inserted through the nose or mouth into the trachea and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue samples of the suspected mesothelioma tumor, which are checked under a microscope for signs of mesothelioma.
Cytologic exam: An exam of cells under a microscope (by a pathologist) to check for anything abnormal. For mesothelioma, fluid is taken from around the lungs or from the abdomen. A pathologist checks the cells in the fluid.
After malignant mesothelioma has been diagnosed, various tests are done to find out if malignant mesothelial cells have spread to other parts of the body and to determine the patients prognosis. The process used to find out if mesothelioma has spread outside the pleura or peritoneum is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the spread of the mesothelioma in order to plan treatment.