Key Takeaways
- Obtaining a correct mesothelioma diagnosis is difficult because symptoms — shortness of breath, coughing, fatigue, weight loss — overlap with many common respiratory conditions like asthma and pneumonia, often leading to initial misdiagnosis.
- The diagnostic process typically follows a step-by-step pathway: chest X-ray → pleural ultrasonography or CT scan with contrast → MRI → biopsy. A diagnosis should never be made based on cytology (cell study) alone.
- Both the American Society of Clinical Oncology and the British Thoracic Society agree that identifying the cell subtype (epithelioid, sarcomatoid, or biphasic) is essential — because each has a different prognosis and may require a different treatment approach.
- European guidelines recommend biopsies obtained through thoracoscopy or CT-guided biopsy. Medscape’s diagnostic guidelines call for chest CT with contrast, thoracentesis for cytologic assessment, and pleural biopsy.
- A patient’s asbestos exposure history — whether occupational or secondhand — is one of the most important early diagnostic clues and should be communicated to the doctor as soon as symptoms appear.
- The earlier mesothelioma is diagnosed, the better the prognosis and the wider the range of treatment options available.
It can be very difficult to obtain a correct mesothelioma diagnosis. There has been research done and guidelines put in place to streamline the process of diagnosis. It is vitally important that someone who is experiencing symptoms of mesothelioma get tested as soon as possible. The earlier the diagnosis, the better the prognosis and the more potential for a better quality of life for the victim. Some symptoms of mesothelioma include shortness of breath, coughing, loss of appetite, unexplained weight loss, and fatigue.
The World Health Organization classifies three different types of mesothelioma: epithelioid, sarcomatoid, and biphasic. Mesothelioma can be hard to diagnose because of the lack of specific symptoms and the lack of specific biomarkers. Symptoms of mesothelioma are similar to other respiratory diseases, such as asthma, so it is common for the cancer to be undiagnosed or misdiagnosed for quite some time.
Steps to Diagnosis
Usually, when a patient initially reports symptoms, the first step to a mesothelioma diagnosis is an X-Ray done by a primary care physician. If an unusual pleurisy, or inflammation of the pleura, is observed, the patient should then be sent to a pulmonologist for further testing. At this point, it is important that the patient try to identify any possible exposures to asbestos that they may have had, either from direct occupational exposure or through secondhand exposure from a family member.
Mesothelioma Diagnosis Through Tests
If a patient is seen to have a pleural effusion after a chest radiograph is performed, the next step is usually pleural ultrasonography. Another option is using a CT scan with contrast, which is written in the British guideline for obtaining a mesothelioma diagnosis. An MRI can be useful to determine the thickness of the tumor and whether it has moved to the diaphragm or the chest wall. A mesothelioma diagnosis should not be made based only on cytology, or the study of microscopic cells and cell structures.
In the European guideline for diagnosing mesothelioma, it is recommended that biopsies are obtained either through thoracoscopy or a CT-guided biopsy.
Medscape lists the guidelines for diagnosing mesothelioma as follows:
- Chest CT with contrast
- Thoracentesis for cytologic assessment
- Pleural biopsy
The American Society of Clinical Oncology as well as the British Thoracic Society both agree that cytology alone should not be used to make a mesothelioma diagnosis. Both societies also believe that it is important to report the subtype of mesothelioma as epithelioid, sarcomatoid, and biphasic mesothelioma have different prognoses and therefore different treatment plans could be needed.
If you or a loved one has received a diagnosis of mesothelioma or another asbestos-related disease, please call (800) 505-6000 or reach out through our contact form for more information. We are here to help.
Frequently Asked Questions
How is mesothelioma diagnosed?
Mesothelioma diagnosis typically follows a step-by-step process:
- Chest X-ray — the first test, usually ordered by a primary care physician when a patient presents with respiratory symptoms. Can reveal pleural inflammation (pleurisy) or fluid buildup.
- Pleural ultrasonography or CT scan with contrast — provides more detailed imaging if the X-ray shows abnormalities
- MRI — used to determine tumor thickness and whether the cancer has spread to the diaphragm or chest wall
- Biopsy — a tissue sample obtained through thoracoscopy or CT-guided biopsy to confirm the diagnosis at the cellular level
Both the American Society of Clinical Oncology and the British Thoracic Society agree that cytology alone should not be used to make a mesothelioma diagnosis.
Why is mesothelioma so hard to diagnose?
Mesothelioma is difficult to diagnose for several reasons. Its symptoms — shortness of breath, coughing, fatigue, and chest pain — are nearly identical to common respiratory conditions like asthma, pneumonia, and bronchitis. The disease is also rare (~3,000 cases/year in the U.S.), so it may not be the first condition doctors suspect. Additionally, mesothelioma lacks specific biomarkers that can conclusively confirm the diagnosis without additional testing. All of this leads to frequent misdiagnosis or delayed diagnosis.
Why does the cell subtype need to be identified during diagnosis?
The World Health Organization classifies mesothelioma into three cell subtypes — epithelioid, sarcomatoid, and biphasic — each with a different prognosis and treatment profile:
- Epithelioid — most common, slowest growing, best response to treatment
- Sarcomatoid — rarest, most aggressive, most treatment-resistant
- Biphasic — contains both cell types, prognosis depends on which is dominant
Without identifying the subtype, doctors cannot select the most appropriate treatment plan. This is why biopsy and tissue analysis are essential parts of the diagnostic process.
What role does asbestos exposure history play in diagnosis?
A patient’s asbestos exposure history is one of the most important early diagnostic clues. Because mesothelioma is caused almost exclusively by asbestos exposure — and because its symptoms mimic so many other conditions — knowing that a patient was exposed to asbestos can prompt doctors to pursue mesothelioma-specific testing sooner rather than treating for other conditions first. This includes both direct occupational exposure and secondhand exposure from a family member’s contaminated work clothes.
Why does early diagnosis improve outcomes?
Mesothelioma is an aggressive cancer with a limited treatment window. Patients diagnosed at earlier stages have access to a wider range of treatments — including potentially curative surgeries — that become unavailable once the cancer has spread. The five-year survival rate for early-stage mesothelioma is approximately 24%, compared to roughly 7% for stage 4. Every step in the diagnostic process that happens faster gives the patient more options and a better chance at extended survival.
What should I do if I’m experiencing symptoms and have a history of asbestos exposure?
If you are experiencing symptoms like persistent cough, shortness of breath, chest pain, or unexplained weight loss and have any history of asbestos exposure, tell your doctor about your exposure history immediately. This single piece of information can change the diagnostic trajectory entirely — prompting your doctor to order mesothelioma-specific imaging and tests rather than treating for more common conditions first. For information about your legal options, call (800) 505-6000 or fill out our contact form for a free consultation.
