Mesothelioma Biopsy

The mesothelioma biopsy involves an invasive surgical procedure, and is the last step in confirming a diagnosis. Before this happens however, there are many other steps that must be taken.

The Difficulties

Mesothelioma is one of the most difficult forms of cancer to diagnose; historically, it is often not confirmed until it has reached its final stage, and then only because the disease has spread to distant parts of the body. This is especially true of the most common variant of the disease, pleural mesothelioma, which affects the lungs and respiratory system.

The primary reason is the lengthy latency period; the initial stages of mesothelioma move very slowly. It can be several decades between initial asbestos exposure and the appearance of symptoms. This is not to say that symptoms are not noticeable during this time. However, these symptoms – breathing difficulties, lack of energy, elevated heart rate, chronic cough and fluid build-up in the chest – are common to a wide range of respiratory disorders, and are often mistaken for bronchitis, emphysema, pneumonia and other lung diseases.  In at least 50% of cases, there are no symptoms until Stage 3 or 4.

Patient History

This is why it is very important for patients to inform their doctors if they have ever worked with or been heavily exposed to asbestos, or have reason to believe they have been. In the presence of such symptoms, with this knowledge a physician can order additional tests as well as images such as x-rays, CT, PET and MRI scans in order to see if there are any unusual masses on the lung.

Taking a Sample

The final confirmation of a mesothelioma diagnosis will come from an actual tissue sample. The patient is placed under local anesthesia, and a small incision is made in the chest wall. A fine tube. called a thorascope, is then inserted and a small sample of tissue is then taken. This sample is examined directly under an electron microscope by human eyes; the pathologist will make a determination from the appearance of the cell structure and run additional tests on the sample. One of these tests, called immunohistochemistry, examines the protein molecules on the surface, looking for the biochemical markers that are signs specific to mesothelioma. Recently, a test known as the DNA Microarray has become available, and allows pathologists to actually look at the genetic structure, which with mesothelioma cells is very distinctive.