Diagnosing Malignant Mesothelioma

Malignant mesothelioma is a rare cancer. It affects the lining of the body’s internal organs and structures, known as the mesothelium. It most often affects the lining of the lungs, but it can also occur in the abdomen and the pericardium, the sac of tissue that surrounds the heart.

The most common cause of this cancer is exposure to asbestos. This naturally occurring but toxic fiber was once used to insulate homes, commercial buildings, and schools. It was also a component of electrical panels in buildings and automobile braking systems.

As health concerns about its use arose, most forms of this material were widely banned in the United States and other countries in the 1980s and 1990s.

People can develop malignant mesothelioma after inadvertently inhaling or ingesting microscopic asbestos fibers in the workplace. For example, people in the construction industry—especially those who work on older homes and buildings—have an increased risk.

The body can’t break down asbestos fibers, so they become lodged in the mesothelium, where they cause scarring, inflammation, pain, and, eventually, cancer.

In many situations, people with the condition did not work directly with asbestos. Rather, spouses or family members who did brought the fibers home on their clothing. Malignant mesothelioma can take 20, 30, or even 50 years to develop after exposure, so diagnosis is often delayed until a person has symptoms and the condition is more advanced.

Diagnostic Tests

To diagnose malignant mesothelioma, NYU Langone doctors perform a physical exam, which may involve listening to the chest with a stethoscope and asking about your symptoms. Doctors also take a medical history, in which they ask about your exposure to asbestos. Then they order a series of tests.


Your doctor orders a chest X-ray, which uses electromagnetic radiation to form an image of the inside of the body. He or she looks for fluid in the chest or abdomen, evidence of asbestos exposure—including calcium deposits known as plaques, which can build up over time but are not cancerous—and diminished size of the lung on one side due to scarring.

CT Scan

For most people, the doctor orders a CT scan after an X-ray. A CT scan uses X-rays and a computer to create cross-sectional images of the body. The test can reveal fluid, as well as thickened areas, in the lining of the lungs or abdomen. This may indicate mesothelioma. A CT scan can also help doctors determine whether the cancer has spread to other areas of the body.

Prior to the scan, your doctor may inject a contrast agent, or dye, into a vein, which highlights any tumors. This painless test typically takes 10 to 15 minutes.


If your doctor finds a suspicious growth during a CT scan, he or she may order a PET/CT scan, which combines PET and CT scans. The CT portion of the test uses X-rays to create cross-sectional images of the body, while the PET scan detects tumor activity.

During a PET scan, a small amount of radioactive glucose, or sugar, is injected into a vein. This substance collects in tumor cells, which are detected by a computer during the scan. The computer then creates three-dimensional images of cancer activity in your body.

A PET/CT scan helps doctors determine whether a growth contains cancer. The scan can also indicate if the cancer has spread throughout the body.

MRI Scan

An MRI scan uses a magnetic field and radio waves to create computerized, three-dimensional images of structures in the body. This test may be used to help doctors determine how far the mesothelioma has spread. Before the test begins, a doctor may inject a contrast agent into a vein to help highlight the structures of the body and any tumors.


If your doctor finds a tumor on an imaging test, he or she performs a biopsy—in which he or she removes fluid or tissue for examination under a microscope—to confirm the diagnosis.

Our experts may use a small needle to remove fluid from the peritoneum or pleura in people with suspected mesothelioma. After numbing the skin with a local anesthetic, a doctor inserts a needle into the abdomen or between the ribs to withdraw fluid for examination under a microscope. Doctors usually use live CT scans to guide the needle during this process. Sometimes, they may use ultrasound to guide the procedure.

A needle biopsy does not require general anesthesia and is a relatively quick procedure. Examining fluid for signs of cancer can be challenging and can make the determination of what type of mesothelioma is present more difficult. However, people may initially choose to have the procedure because it is less invasive than a surgical biopsy.

During a surgical biopsy, a doctor makes an incision in the chest or abdomen and removes tumor tissue from the pleura or peritoneum for further testing. This procedure is performed using general anesthesia. A surgical biopsy can help confirm a diagnosis of malignant mesothelioma. It may also be performed to determine how advanced the cancer is and to help a doctor choose the most effective treatment.


Thoracoscopy is a procedure used to determine whether—and how far—the cancer has spread in the chest. A thoracoscope is a thin, lighted tube with a video camera on the end. Your doctor makes a small incision between the ribs and inserts the thoracoscope, which enables him or her to examine the pleural cavity and lining for signs of cancer. Doctors place small surgical tools through the scope and use them to remove tissue samples.

This procedure can also be used to biopsy any tumors on the outer parts of the lungs and lymph nodes in the area. Fluid in the pleural cavity may also be removed for additional evaluation to see if cancer cells may be present.

Thoracoscopy, which is also called pleuroscopy, may require general anesthesia, and you may need stay in the hospital overnight so doctors can monitor you and manage any discomfort. In some people, the procedure can be performed through a single, small incision using local anesthesia and sedation.


A laparoscopy is similar to a thoracoscopy, except doctors make small incisions in the abdomen through which they pass a laparoscope—a thin, lighted tube with a camera on it—to see whether cancer is in the peritoneum. Doctors insert surgical tools through the scope to remove tissue samples for examination under a microscope.

This test requires general anesthesia, and you may need to stay in the hospital overnight so doctors can monitor you and manage any discomfort.

Endobronchial Ultrasound-Guided Needle Aspiration

Our surgeons may perform an endobronchial ultrasound-guided needle aspiration to determine whether the mesothelioma has spread to lymph nodes in the center of the chest.

For this procedure, a doctor inserts a bronchoscope, a long, flexible tube with an ultrasound device on the end, through the mouth and into the airways. The surgeon performs the procedure using moderate or deep sedation. The ultrasound device uses sound waves to create pictures of the structures surrounding the airways on a computer monitor. This allows doctors to identify enlarged and potentially cancerous lymph nodes.

When the enlarged lymph nodes are identified, the doctor threads a tiny needle through the bronchoscope to take tissue samples. This procedure is performed on an outpatient basis, meaning you can typically go home the same day.


Another procedure for determining whether mesothelioma has spread to the lymph nodes in the center of the chest is a mediastinoscopy. In many instances, our specialists use it to confirm negative biopsy results from an endobronchial ultrasound.

During mediastinoscopy, a doctor makes a small incision in the neck and inserts a mediastinoscope, a thin tube that resembles an endoscope with a video camera on the end.

The mediastinoscope is placed in front of the trachea, where the surgeon can view a group of lymph nodes. The images appear on a computer monitor. The doctor inserts surgical tools through the scope to remove tissue samples from the lymph nodes.

Doctors use general anesthesia for mediastinoscopy, but people can usually go home the same day. Our nurses and specialists manage any discomfort you may have from the procedure.

Clinical Trials

NYU Langone’s Thoracic Oncology Research Program is recognized as a Biomarker Discovery Laboratory by the National Cancer Institute. Biomarkers are substances in the blood that indicate whether cancer may be present. The program explores ways to detect mesothelioma earlier.

Doctors at NYU Langone are studying certain proteins in the blood in the hopes of distinguishing people who may have been exposed to asbestos from those who actually have mesothelioma.

Researchers are also using these biomarkers to help diagnose mesothelioma early in people who are at high risk of developing the condition because of prior exposure to asbestos. These proteins could also be used to monitor the cancer’s response to therapy.

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