Diagnosis and testing

Several tests can be used to help in making the diagnosis of mesothelioma, including a chest x-ray, a CT scan, and a MRI scan. A chest x-ray yields an image of the lungs that will show many types of abnormal changes. A CT scan (computed tomography) is a type of x-ray, but it uses a computer rather than film and creates more detailed images than a x-ray. A MRI scan (magnetic resonance imaging) uses magnetism, radio waves, and a computer; and it does not use x-ray radiation. These tests help your doctor differentiate mesothelioma from other lung tumors as well as determine where the tumor is and its size.

Your doctor may need to remove a tissue sample from the tumor, which is called a biopsy, or draw fluid from the tumor to confirm the diagnosis. This can be done several ways.

The simplest way to obtain tissue samples is to make a small incision and place a flexible tube in the area of the tumor. When this procedure is done in the chest area it is called a thoracoscopy. When it is done in the abdominal cavity, it is called a laparoscopy. A tube with an attached small video camera is placed inside the body so the doctor can see the area in greater detail. A tissue sample may be taken at the same time. Sometimes, however, a more extensive surgical procedure may be advisable. A thoracotomy can be done through an incision in the chest to take a biopsy and, if feasible, to remove most or all of the visible tumor. If this procedure is done in the abdominal cavity, it is called a laparotomy.

At other times, a mediastinoscopy may be done in which a very small incision is made just above the sternum (breast bone) and a tube is inserted just behind the sternum. This lets the doctors look at lymph nodes. Lymph nodes are small, bean-shaped structures that are an important part of the body’s immune system, and they contain cells that help your body fight infection as well as cancer. This test will give the doctor more information on the type of cancer and whether it has spread to other areas. The tissue samples taken in these procedures are analyzed by looking at them under a microscope to determine whether the tumor is mesothelioma or another type of cancer.