Mesothelioma Diagnosis

Diagnosing mesothelioma is not always a simple task. Because mesothelioma is so rare, doctors commonly mis-diagnose mesothelioma as other diseases with similar symptoms. Additionally, because mesothelioma has such a long latency period, or period of time in which the disease remains without symptoms, timely diagnosis is often times quite difficult. Typically symptoms of mesothelioma are not present for decades after exposure, and usually once symptoms are present the cancer has already reached stages in which it is not treatable. Because of the serious nature of mesothelioma, it is crucial for those who have been exposed to asbestos to be screen yearly for lung disease.

Pleural mesothelioma affects the mesothelium lining in the chest cavity and lung, and is known as the most common type of mesothelioma. Other types of mesothelioma include the peritoneal and pericardial mesothelioma, which affect the abdominal mesothelium and mesothelium surrounding the heart, respectively. In pleural mesothelioma, patients usually first notice symptoms that are common in many illnesses and diseases. Most patients complain of chest pain and shortness of breath, usually accompanied by back pain. Less common symptoms include difficulty walking, trouble swallowing, weight loss and fatigue. Because the disease affects the respiratory system breathing tends to become more and more difficult as the disease advances.

To diagnose mesothelioma, doctors will usually order several different scans, radiological tests, and biopsy samples to be taken. CT (or CAT) scans, X-rays and MRI scans are usually taken to detect the presence of mesothelioma. Scans are usually followed by taking samples of the fluid surrounding the lungs. However, the only way to make a firm diagnosis is by collecting samples of infected tissue by biopsy.

The most common radiological tests ordered in mesothelioma diagnosis are CT (or CAT) scans, X-rays, and Magnetic Resonance Imaging or MRI scans. While none of these scans is able to conclusively diagnose mesothelioma, they are helpful in detecting how far the cancer has spread, as well as what stage the cancer is in.

CT scans are able to detect pleural effusion (or fluid build up), pleural thickening, pleural calcification, thickening of interlobular fissures, and chest wall invasion. CT scans also help doctors to detect where a biopsy incision should be made, and were to insert the needle in needle biopsy. However, CT scans are not able to distinguish between Adenocardinoma which may have spread to the pleura and mesothelioma.

X-Rays also help doctors to detect pleural effusion, tumor masses, pleural plaques and pleural calcification (both non-cancerous diseases), and scarring due to asbestos exposure or asbestosis.

MRI scans are most often commonly used to determine the size of tumors. MRI scans can provide images in multiple planes, and they are able to identify tumors as opposed to normal lung mass better than other types of radiological scans. MRI scans also can detect the enlargement of mediastinal lymph nodes (or the lymph nodes which lie between to two lungs).

While radiological scans are obviously important, the only way to confirm a mesothelioma diagnosis is to collect a sample of tissue by biopsy. To collect pleural biopsies, the doctor may perform a small operation in order to remove a small piece of tissue from the lung. Likewise, tissue collected from the abdominal areas are known as peritoneal biopsies, and biopsies are collected by a tool called the peritoneoscope. Open biopsies are usually done in a hospital setting, with the patient under anesthetic. Although open biopsies are the most effective in collecting cells and conclusively diagnosing mesothelioma, there are several other biopsy procedures that doctors may use which are less invasive than the open biopsy.

Typically, Doctors will perform a thorascopy or laparoscopy, or a needle biopsy as an alternative to open biopsy. To perform a thorascopy or laparoscopy, doctors will make a small incision and insert a camera to look at the infected area. A sample of tissue is also taken by the thorascope, which is then examined by a pathologist for possible infection. The needle biopsy involves inserting a hollow needle through the skin into the chest cavity where cells are collected in the inside of the needle and then analyzed by a pathologist.

After cells have been collected, pathologists will examine the cells in detail to check for possible infection. If fluid has collected in the chest cavity or abdominal cavity, doctors can drain the fluid by inserting a needle with a gentle suction method using what is called thoracentesis or paracentesis, respectively. This fluid can also be analyzed for infection. If a diagnosis is made doctors will then determine what stage the cancer is in and what course of treatment should be taken.

Last modified: April 29, 2009