Mesothelioma Diagnosis

Quick Summary

To diagnose mesothelioma doctors take multiple steps starting by examining a patient’s symptoms and asbestos exposure history, and finishing with a biopsy tested in a pathology lab. Only mesothelioma specialists have the experience required to accurately diagnose this rare cancer type.

Mesothelioma Diagnosis Overview

If you are experiencing mesothelioma symptoms and have a known history of asbestos exposure, then you may be diagnosed with a form of mesothelioma. Here is what every patient needs to know about diagnosing mesothelioma:

  • Only mesothelioma specialists can diagnose this rare type of cancer
  • Mesothelioma is diagnosed by location, stage and cell type
  • Doctors use tests like imaging scans and bloodwork to help them diagnose mesothelioma
  • A biopsy (sample of cancerous tissue) can confirm a mesothelioma diagnosis
  • Patients are within their rights to seek a second opinion if they question their initial diagnosis

How Mesothelioma is Diagnosed

Mesothelioma can only be accurately diagnosed by specialists who have years of experiencing researching and treating this rare disease. Unfortunately, because mesothelioma is so rare, it often gets misdiagnosed by the patient’s general practitioner when symptoms are initially reported. Even if cancer is suspected, general oncologists (cancer doctors) don’t always have the experience that’s necessary to identify such a complex disease.

With a proper diagnosis, doctors can determine the mesothelioma cell type and disease stage. It’s critical for doctors to know a patient’s unique diagnostic factors so that they can develop the most effective treatment plan possible.

Diagnosis Update

Doctors, either general practitioners or general oncologists, can refer patients to specialized mesothelioma surgeons across the country. Referrals are the usual way that patients are able to set up consultation appointments with mesothelioma specialists to get a proper diagnosis.

Here are the steps that doctors take to diagnose mesothelioma:

1. Physical Examination

Typically, when patients begin to notice persistent symptoms, they will report their condition to their family doctor. If you suspect you have any of the signs or symptoms of mesothelioma, then it’s critical to inform your doctor of your history of asbestos exposure—the only known cause of mesothelioma.

During a physical exam:

  • Doctors ask patients about their symptoms and how long they’ve lasted
  • Doctors will listen to a patient’s chest to detect congestion or fluid buildup
  • Patients should report their history of asbestos exposure

It’s possible for a physician to suspect conditions like bronchitis or pneumonia, which are far more common than mesothelioma—making it vital for patients to alert their doctors to their history of asbestos use.

2. Imaging Scans and Tests

Based on the physical examination, doctors may suspect pleural effusions (fluid buildup in the chest), or malignancy (cancer). To investigate further, doctors will order one or multiple imaging tests. Image scanning machines help doctors look inside you to find abnormalities.

Different scans look for different things, and doctors might order tests such as:

  • X-Ray: X-ray is one of the most common imaging tests doctors use when making many different diagnoses. A chest x-ray shows doctors a 2D image of the chest cavity and can reveal abnormalities such as a tumor mass or fluid buildup.
  • CT Scan: During a CT (computed tomography) scan, the machine rotates around the patient taking multiple x-ray images. CT scans show cross-sectional images, which provide much more detail than a 2d x-ray image. CT scan images allow doctors to find an exact tumor location, which is helpful for staging cancer.
  • PET Scan: PET (positron emission tomography) scans use radioactive substances to determine if cancer cells are present. Doctors inject the substance into your bloodstream, which gets absorbed by cancer cells if there are any. A PET scanner takes pictures of your body and reveals which areas are radioactive. Though PET scans don’t provide enormous detail, they can help doctors determine if the abnormalities seen in CT scans or x-rays might be cancerous.
  • MRI: Magnetic Resonance Imaging scans show detailed images of tissues. Prior to the exam, you are injected with a substance that reveals contrast so doctors can see tissues in greater detail. An MRI is a lengthier process than other tests and involves being in an enclosed tube, which can be frightening for some patients. There are facilities that offer an open MRI that are used to accommodate claustrophobic and obese patients. The open MRI is usually open on two or three sides and can provide a more relaxed, less confining space reducing stress in many patients than the traditional MRI. Be sure to talk to your doctors about any concerns you have with this type of test.

3. Blood Tests and Biomarkers

Biomarker and blood tests identify levels of certain substances that may be higher in mesothelioma patients. Blood and biomarker tests are helpful for doctors because they give more details about mesothelioma. These tests are often used to help support the results from imaging tests.

There are several blood and biomarker tests that doctors have used over the years to help identify mesothelioma. Some of these substances may be more promising indicators than others, but they can help alert doctors to mesothelioma.

The following are some of the substances doctors can test for to help them identify mesothelioma:

  • CA125 (Cancer Antigen)
  • Fibulin-3
  • High mobility group B1 (HMGB1)
  • Megakaryocyte potentiating factor (MPF)
  • MicroRNAs (miRNAs)
  • Multiplex protein signatures
  • Osteopontin
  • Soluble mesothelin-related peptides (SMRPs)—tested with the MesoMark® Test

4. Biopsies

The only way to conclusively diagnose mesothelioma is by testing the abnormal tumor mass for cancer cells. The previous steps are conducted to help guide doctors in the right direction so they can make the final diagnosis.

Biopsies are a surgical procedure whereby tissue samples are taken from the body to be looked at under the microscopic. Pathologists are doctors who study these tissue samples to determine the types of cancer cells that are present.

There are a few ways doctors collect samples for biopsies:

  • Thoracoscopy: Using a thin tube with a tiny camera, doctors look inside the chest and lungs to find tumors and withdraw samples.
  • Laparoscopy: Like a thoracoscopy, doctors use a tiny camera to look inside the abdomen for tumors from which they can take small samples.
  • Mediastinoscopy: Using a tiny camera, doctors look inside the part of the lungs called the mediastinum. Doctors pull tissue samples from the lymph nodes in this area.
  • Thoracotomy: As an open surgical process, a thoracotomy allows the doctor to look inside the chest cavity to collect samples and see the extent of the cancer.
  • Laparotomy: With a laparotomy, doctors open up the abdominal cavity to collect tissue samples and view the extent of the disease.

As an alternative to collecting tissue samples, doctors may take fluid samples from the chest, abdomen or heart to help detect mesothelioma cells. Fluid sample collection and testing is cytology.

To remove fluid from these areas, doctors use a small hollow needle to drain and collect fluid into a catheter. Then the fluid is tested for the presence of cancer cells. In diagnosing mesothelioma, fluid testing is not as conclusive as surgical biopsies.

Mesothelioma Histopathological Reports

With the biopsy samples, doctors then determine what type of cancer is present—a field known as histopathology. By examining the samples under a microscope, doctors look for certain cellular characteristics that correspond to specific types of cancer.

Mesothelioma tumors have 3 cell types—epithelioid, sarcomatoid and biphasic—and doctors look to see which cell types are involved.

Mesothelioma cell type is incredibly important information for a diagnosis because it informs the treatment plans that doctors establish for their patients.

Visit our page on Mesothelioma Cell Types to learn more about this crucial diagnosis factor.

Mesothelioma Misdiagnosis

With only 3,000 cases a year, mesothelioma is a relatively rare cancer compared to other types such as lung cancer, which has over 234,000 cases per year in the United States. Given its rarity, the vast majority of doctors will never encounter a case of mesothelioma.

Mesothelioma has a high misdiagnosis rate because it can easily be mistaken for conditions doctors are more familiar with, such as pneumonia or gastrointestinal conditions.

Because it is so hard to catch, some patients may go on for months or even longer before they are properly diagnosed with mesothelioma. By then, the disease has often reached an advanced stage.

Even if doctors are able to identify the condition as cancerous, it can often be mistaken for other types of cancer. Common cancers that mesothelioma may be mistaken for include lung and breast cancers as well as lymphoma or abdominal cancers. A misdiagnosis is a serious problem because mesothelioma requires vastly different treatment plans than any of these other cancer types.

Mesothelioma Second Opinion

Only mesothelioma specialists are familiar with the unique characteristics of mesothelioma that make it such a complex cancer. If you’ve seen a general oncologist, it’s critical to get a referral to a mesothelioma specialist to obtain a second opinion.

Not only do mesothelioma specialists have the experience to accurately identify this cancer type, they also have the expertise required to stage cancer properly, which ultimately determines a patient’s treatment options.

There have been cases whereby patients were diagnosed with mesothelioma but the staging was incorrect. Getting a second opinion from another mesothelioma specialist is important because doctors have diverse experiences. One doctor may be more willing to aggressively treat advanced mesothelioma stages than others, which can give patients more treatment options.

Improving Prognosis After Mesothelioma Diagnosis

Obtaining a proper mesothelioma diagnosis is critical to receiving the best possible treatments for your condition. A diagnosis tells doctors not only where the mesothelioma is located, but also the cell type and how far it has advanced. Without the full picture, doctors cannot offer the most effective treatments.

Getting on the right personalized treatment plan is the best way to extend your life expectancy.

Mesothelioma specialists are available across the country to help you obtain the correct diagnosis. From a diagnosis, doctors can tailor a treatment plan specific to your unique case and can help you improve your prognosis. Contact a Mesothelioma Help Now Patient Advocate today to learn more about working with top mesothelioma specialists.

Because [mesothelioma is] so rare, it really is best handled by surgeons who’ve seen many of these patients at experienced centers.  — Dr. Sarah B. Goldberg, MD, MPH, assistant professor of medicine, Yale School of Medicine and Yale Cancer Center

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View Author and Sources

  1. American Cancer Society, “How is Malignant Mesothelioma Diagnosed?” Retrieved from: Accessed on December 27, 2017.
  2. Journal of Thoracic Disease, “Guidelines for the diagnosis and treatment of malignant pleural mesothelioma.” Retrieved from: Accessed on December 27, 2017.
  3. Translational Lung Cancer Research, “Diagnostic and prognostic biomarkers for malignant mesothelioma: an update.” Retrieved from: Accessed on December 27, 2017.
  4. Dr. Goldberg Discusses the Diagnosis of Mesothelioma. YouTube. April 2, 2019. Accessed April 7, 2019.

Last modified: April 8, 2019