Mesothelioma Diagnosis
The most definitive way to diagnose mesothelioma is through a mesothelioma biopsy and corresponding pathology report. Other tests like CT scans, MRIs, PET scans, physical exams and X-rays can support the diagnosis process. Early detection may improve outlook, treatment options and quality of life.
Learn About Mesothelioma Diagnosis in Our Free Guide
How Is Mesothelioma Diagnosed?
Diagnosing mesothelioma involves several tests, including a biopsy. The process often begins when a patient shows symptoms of mesothelioma. But mesothelioma symptoms can be vague, which may lead to misdiagnosis. Patients should share any known history of asbestos exposure with their doctors. This information can help ensure the right tests are ordered.
A simple way to think about it is to break up the diagnosis into two phases:
- Phase 1: The first phase of diagnosis includes general exams and tests.
- Phase 2: The second phase of diagnosis includes specific tests for mesothelioma and cancer.
In the first phase, the patient discusses their full medical history with a doctor. This helps the doctor get information that can narrow down the possibilities. When discussing medical history, the patient has an opportunity to mention asbestos exposure.
The doctor may then conduct a physical exam to look for any lumps or abnormalities. Basic imaging tests, like an X-ray, and blood work may follow. Doctors use blood tests to check a patient’s overall health and organ function. This may also help rule out other conditions.
The second phase involves more advanced diagnostic procedures. The doctor might request specific blood tests. They might also order advanced imaging scans if they suspect mesothelioma. Imaging scans may include:
- Computed tomography (CT)
- Echocardiogram
- Magnetic resonance imaging (MRI)
- Positron emission tomography (PET)
Next, the doctor may order a mesothelioma biopsy, which is a procedure to remove a sample of the suspicious tissue or fluid. Testing a biopsy tissue sample is the only way to confirm a mesothelioma diagnosis. There are many ways a doctor might perform a mesothelioma biopsy, and the method depends on the patient’s case.
A pathology laboratory tests the tissue and fluid samples to learn more about the cancerous cells. Doctors use the test results to determine cell type and other cancer characteristics.
How Do Doctors Test for Mesothelioma?
Doctors generally use several tests to find the cause of their patients’ symptoms. Some common tests include blood tests and imaging scans. These tests may help the doctor diagnose the patient, but biopsies are the only way to confirm a patient has mesothelioma.
Imaging Scans for Mesothelioma
Different imaging tests help doctors identify tumors, their location and metastasis of cancer. Doctors may use X-rays, MRIs, CT scans, PET scans or ultrasounds when diagnosing mesothelioma.
- X-rays: X-rays identify abnormalities and help rule out other conditions. Doctors may use an X-ray to reveal common mesothelioma symptoms. These symptoms may include pleural effusions or peritoneal effusions.
- CT scans: CT scans take a series of X-rays to make a detailed, three-dimensional image of the body. CT scans are an important tool in diagnosing all types of mesothelioma.
- MRI scans: MRIs create intricate images of bones and soft tissue. Doctors use them to find out if mesothelioma has spread into nearby or distant tissues. Doctors also may use the scan as part of the staging process.
- PET scans: PET scans visualize areas of quickly dividing cells, including tumors. This helps distinguish between normal and cancerous tissue. These scans are helpful in showing metastasis.
Mesothelioma tumors may be identified through imaging studies such as a CT scan but a diagnosis can only be determined through examination of tumor cells. These cells can be collected through a thoracentesis or paracentesis in which fluid is taken from the lungs or abdominal cavity, or through a surgical biopsy.
Vincent Mase, MD
Mesothelioma Biopsy
Biopsies are the only way to confirm a mesothelioma diagnosis. These tests involve removing a fluid or tissue sample for analysis. Biopsies help doctors confirm the diagnosis, stage, cell type and type of mesothelioma. Once a mesothelioma biopsy confirms the diagnosis, the medical team can determine treatment options.
There are four types of biopsies commonly used for mesothelioma diagnosis:
- Fluid drainage: Fluid drainage is the least invasive biopsy option. This procedure collects fluid from pleural, peritoneal or pericardial effusions using a needle or catheter. Doctors may drain the fluid sample through thoracentesis, an outpatient procedure. But, in most instances, a fluid sample is not good enough to confirm a mesothelioma diagnosis.
- Needle biopsies: Doctors use a needle biopsy to extract a tissue sample from an affected area. In suspected cases of pleural mesothelioma, the tissue samples may be taken from the pleura (lining of the lung) or a lymph node.
- Surgical biopsies: Surgical biopsies are the most invasive biopsy procedure. Doctors may use this biopsy when mesothelioma tumors are difficult to reach. Surgical biopsies used for mesothelioma include thoracotomy and laparotomy.
- Surgical camera-assisted biopsies: These biopsies start with a small incision. Then, the doctor places a tube and passes a small camera through it into the affected area. Doctors can then locate and retrieve any suspicious-looking tissue for analysis. Types of camera-assisted biopsies used for mesothelioma include thoracoscopy, laparoscopy and mediastinoscopy.
Blood and Tissue Tests for Mesothelioma
A mesothelioma doctor may use blood tests to check overall patient health and to find specific markers that suggest cancer. Doctors generally use tissue tests to make a diagnosis.
Blood tests alone cannot diagnose mesothelioma. But they may guide the doctor towards a diagnosis. For example, the complete blood count (CBC) can identify changes in blood cell and platelet levels. More advanced tests can find specific markers that point to a mesothelioma diagnosis.
The only way a doctor can confirm a mesothelioma diagnosis is to examine cells from the abnormal area. The doctor collects these tissues during a mesothelioma biopsy and sends them to a lab where they are examined. Specialists then test the samples to determine which types of cells they contain.
Doctors may diagnose mesothelioma if the tests on the abnormal tissues find mesothelioma traits. Abnormal tissues that do not have mesothelioma properties may suggest a different condition.
How Does Pathology Help With Diagnosing Mesothelioma?
Pathology is the study of how a disease develops and affects a person. Pathology testing can identify and conclusively diagnose mesothelioma. Mesothelioma pathology includes two types of testing: histology and cytology.
- Cytology analyzes individual cells and their properties. Cytopathology does the same thing with cells affected by diseases, including mesothelioma. Cytopathology testing can help identify specific mesothelioma cell types. In general, cytology alone cannot diagnose mesothelioma. But it can help doctors order more tests that can confirm a diagnosis.
- Histology analyzes tissue samples like those of a mesothelioma biopsy. Histopathology does the same thing with tissues affected by diseases, including mesothelioma. Histopathology testing can use special dyes to identify markers of mesothelioma. This form of testing can confirm a mesothelioma diagnosis.
Doctors use pathology testing to confirm a mesothelioma diagnosis. Patients can help doctors order the right tests by sharing any known history of asbestos exposure. This may speed up the diagnostic process and help ensure timely mesothelioma treatment.
Did You Know?
Choosing the right treatment center when diagnosed with mesothelioma may extend your survival.
Mesothelioma cancer centers offer access to the country’s top doctors and treatment options, as well as clinical trials for emerging treatments.
Does Screening Help Detect Mesothelioma Early?
There is no officially recognized test to detect mesothelioma early. But researchers continue to study possible early detection methods.
Doctors may recommend routine monitoring to patients with past exposure to asbestos. Some people who work in at-risk occupations for asbestos exposure may have mandatory screenings. These screenings may include:
- Chest X-rays
- Pulmonary function tests
- Specific physician-ordered lab tests
Mesothelioma symptoms can take decades to show up. The time between initial asbestos exposure and the onset of symptoms is called the latency period. For mesothelioma, the latency period commonly ranges from 10 to 50 years. Monitoring may help doctors detect signs of the disease earlier. Getting diagnosed and treated earlier has been linked to better patient outcomes.
For example, patients with stage 1 or stage 2 mesothelioma may be able to undergo multimodal treatment. This approach often includes surgery. These treatments have improved life expectancy for many mesothelioma patients.
Those diagnosed at stage 3 or stage 4 mesothelioma may have fewer treatment options. But the available treatments can still extend survival. In general, patients with advanced mesothelioma have a more favorable prognosis with treatment.
Doctors may also recommend palliative therapies. These treatments aim to reduce symptoms, improve comfort and potentially extend life expectancy.
Why Is It Hard to Get an Accurate Mesothelioma Diagnosis?
Doctors may have trouble accurately diagnosing mesothelioma for many reasons. It shares symptoms with other illnesses and is very rare. Only about 3,000 new cases are diagnosed in the United States each year.
Non-specialized doctors may have never seen or treated mesothelioma. This may make them more likely to misdiagnose mesothelioma. A few common misdiagnoses include:
- Breast cancer
- Bronchitis
- Diverticulitis
- Emphysema
- Lung cancer
- Pneumonia
Patients may want to get a second opinion because misdiagnoses do happen. People with known asbestos exposure should see mesothelioma experts for their second opinions. Research suggests a second opinion from a mesothelioma expert may lead to better patient outcomes.
Getting the Best Treatment if Diagnosed With Mesothelioma
Patients may help ensure the most effective treatment by seeking out mesothelioma experts. These specialists have experience treating mesothelioma. They may be able to provide more accurate staging and better treatment options.
Find a Downloadable List of Questions for Your Doctor Here
Mesothelioma patients have an array of treatment options. Several have already helped some patients outlive their original prognoses. And research has expanded treatment options in recent years. As additional clinical trials take place, more treatment options may become available.
For example, research into checkpoint inhibitor drugs has led to improved outcomes. The drugs Opdivo® (nivolumab) and Yervoy® (ipilimumab) have more than doubled survival for some patients. Plus, advancements in chemotherapy treatments, such as HIPEC and HITHOC, have also helped many patients. Patients who seek treatment at experienced cancer centers may have easier access to these and other therapies.
Have a Question About Mesothelioma Testing? Ask experienced mesothelioma advocate Jennifer Lucarelli Ask a Question
Common Questions About Mesothelioma Diagnosis
How difficult is it to diagnose mesothelioma?
How do you detect mesothelioma early?
No diagnostic test has approval for early diagnosis of mesothelioma. Early detection depends on if the doctor knows the patient has been exposed to asbestos. With this knowledge, doctors can monitor for signs of the disease using:
- Chest X-rays
- Pulmonary function tests
- Specific physician-ordered lab tests
How long does diagnosing mesothelioma take?
What definitive tests are available to diagnose mesothelioma?
I have been diagnosed with mesothelioma — now what?
Sources
Alexander HR, Burke AP. Diagnosis and management of patients with malignant peritoneal mesothelioma. J Gastrointest Oncol. 2016 Feb;7(1):79–86.
American Cancer Society. Key Statistics About Malignant Mesothelioma.
American Cancer Society. Tests for Malignant Mesothelioma.
American Lung Association. Pneumonia Symptoms and Diagnosis.
Bianco A, Valente T, De Rimini ML, Sica G, Fiorelli A. Clinical diagnosis of malignant pleural mesothelioma. J Thorac Dis. 2018 Jan;10(Suppl 2):S253–61.
Bono F, Ceola S, Beretta C, Jaconi M. Unusual Histology in Mesothelioma: A Report of Two Cases with a Brief Review. Diagnostics (Basel). 2022 Feb 1;12(2):371.
Cancer Council Victoria. Mesothelioma.
Churg A, Galateau-Salle F, Roden AC, Attanoos R, von der Thusen JH, Tsao MS, et al. Malignant mesothelioma in situ: morphologic features and clinical outcome. Mod Pathol. 2020 Feb;33(2):297–302.
Cleveland Clinic. Blood Tests for Cancer.
Husain AN, Colby TV, Ordóñez NG, Allen TC, Attanoos RL, Beasley MB, et al. Guidelines for Pathologic Diagnosis of Malignant Mesothelioma: A Consensus Statement from the International Mesothelioma Interest Group. Arch Pathol Lab Med. 2018 Jan;142(1):89–108.
Lucà S, Pignata G, Cioce A, Salzillo C, De Cecio R, Ferrara G, et al. Diagnostic challenges in the pathological approach to pleural mesothelioma. Cancers (Basel). 2025 Feb 1;17(3):481.
Mayo Clinic. Mesothelioma.
National Comprehensive Cancer Network. Mesothelioma: Pleural Version 2.2025.
National Cancer Institute. Cancer Staging.
Pass HI, Alimi M, Carbone M, Yang H, Goparaju CM. Mesothelioma Biomarkers: A Review Highlighting Contributions from the Early Detection Research Network. Cancer Epidemiol Biomarkers Prev. 2020 Dec;29(12):2524–40.
Popat S, Baas P, Faivre-Finn C, Girard N, Nicholson AG, Nowak AK, et al. Malignant pleural mesothelioma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up☆. Ann Oncol. 2022 Feb;33(2):129–42.
Shah R, Klotz LV, Glade J. Current management and future perspective in pleural mesothelioma. Cancers (Basel). 2022 Feb 18;14(4):1044.
Zarogoulidis P, Tsakiridis K, Zarampoukas T, Zarampouka K, Hatzibougias D, Tolis C, et al. Mesothelioma: A Case in a Diagnostic Timeline and the Efficiency of Robot-Assisted Surgery. Case Rep Oncol. 2022;15(1):149–55.
Free Mesothelioma Treatment Guide
Katy Moncivais, Ph.D., has more than 15 years of experience as a medical communicator. As the Medical Editor at Mesothelioma.com, she ensures our pages and posts present accurate, helpful information.
Medically
Reviewed by
James Stevenson, MD
Thoracic Medical Oncologist
Dr. James Stevenson is a Board-Certified Medical Oncologist. He specializes in treating mesothelioma and lung cancer and practices at the Cleveland Clinic in Cleveland, Ohio.
