Pleural Mesothelioma Diagnosis

Quick Summary

Pleural mesothelioma is a rare diagnosis with fewer than 3,000 cases annually in the United States. To diagnose mesothelioma, specialized oncologists follow specific steps to help them determine the type and stage of pleural mesothelioma. Obtaining an accurate diagnosis is critical to effectively treating patients and extending their lives.

Pleural Mesothelioma Diagnosis Overview

If you suspect you have symptoms of pleural mesothelioma and you have a known history of asbestos exposure, then it’s vital to see a mesothelioma specialist to obtain an accurate diagnosis.

Here is what everyone who suspects they may have pleural mesothelioma needs to know about diagnosing this rare disease:

  • Only a pleural mesothelioma specialist can diagnose your condition
  • Doctors diagnose pleural mesothelioma by cell type and stage
  • Image scans, blood tests, and tissue samples help doctors diagnose pleural mesothelioma
  • A biopsy (cancer tissue testing) is the only way to conclusively diagnose mesothelioma
  • Pleural mesothelioma is commonly misdiagnosed as pneumonia or bronchitis or is mistaken for another type of lung cancer
  • All patients should seek a second opinion on their pleural mesothelioma diagnosis from another specialist

How Pleural Mesothelioma is Diagnosed

Pleural mesothelioma can only be accurately diagnosed by a pleural mesothelioma specialist. As doctors with years of experience treating and researching pleural mesothelioma, specialists are very familiar the disease intricacies.

Pleural mesothelioma is complex. Its symptoms develop 10-50 years after initial asbestos exposure (the only known cause), and can often mimic other conditions. Additionally, mesothelioma cells can be confused with other cancer cell types, such as common lung cancers.

Pleural mesothelioma also requires substantially different treatment plans than other cancers, making an accurate diagnosis a matter of life or death for patients. To undergo life-saving treatment, patients must have their condition accurately diagnosed by cell type and stage, as different cell types and stages require their own treatments.

Diagnosing pleural mesothelioma involves multiple steps, and the entire process can take several weeks or months to accurately identify the condition.

Here are the steps involved in diagnosing pleural mesothelioma:

  1. Physical Examination
  2. Image tests
  3. Blood and biomarker tests
  4. Biopsies

Patients see several different doctors of various specialties throughout the diagnosis process. Each doctor has their own role to play that will ultimately lead to the final diagnosis.

1. Physical Examination

Patients first report their pleural mesothelioma symptoms to their general practitioner. The most common symptoms patients report is chest pain, persistent cough and shortness of breath. Doctors examine their patients, which includes listening to their chest. With a stethoscope, doctors can hear fluid buildup and congestion, which may alert them to pneumonia or bronchitis.

It’s critical for patients to disclose their history of asbestos exposure to their doctor at this point. Discuss details such as your occupation or the home you lived in. This can help doctors identify mesothelioma quicker.

2. Image Tests

When doctors hear chest congestion and fluid buildup, they may order a series of imaging tests to see inside your chest and look for abnormalities.

Common tests involved in diagnosing pleural mesothelioma include:

  • Chest X-Ray: An x-ray machine takes a 2D image of the inside of your chest cavity. It can show doctors abnormal masses of tissue, which can either be malignant (cancerous) or benign (non-cancerous).
  • CT Scan: CT (computed tomography) scans take a series of images around the chest to show doctors any abnormalities in greater detail. Doctors need to know the exact location of the tumor mass and how far it has spread, and CT scans help them do this.
  • PET Scan: PET (positron emission tomography) scans use radioactive substances to show cancer cells. Doctors inject the substance into your blood, which circulates and is absorbed by cancer cells. Then the PET scanner takes images to reveal the radioactive areas in the body. PET scans help doctors determine if the masses might be cancerous, but not what type of cancer.

It’s important for pleural mesothelioma patients to know that imaging scans only help doctors identify abnormalities in the chest. Scans don’t tell conclusively doctors whether you have cancer nor do they tell doctors what type of cancer you have.

3. Blood and Biomarker Tests

With many diseases, doctors can identify the condition and its prognosis by testing for certain  “biomarkers” substances in the patient’s body. Researchers have identified a few biomarkers associated with pleural mesothelioma, though none of them have conclusively been linked to mesothelioma.

One of the tests that doctors may order if they suspect mesothelioma is called the MesoMark® test, which shows levels of soluble-mesothelin related protein (SMRP). If a patient tests positive for high levels of this protein, it can move doctors closely towards a pleural mesothelioma diagnosis.

4. Biopsies

When doctors want to confirm whether tissue masses are malignant or benign, they order biopsies. By taking samples of pleural tissue or fluid, doctors can test them for the presence of cancer cells.

For pleural mesothelioma, doctors have a few biopsy options:

  • Thoracentesis: Using a hollow needle, doctors withdraw pleural fluid and drain it into a catheter. Pleural fluid isn’t always a reliable indicator of mesothelioma cells because fluid doesn’t always show cancer cells, which can lead to false negatives.
  • Thoracoscopy: Doctors frequently use a thoracoscope—a tiny camera inserted into the chest—to diagnose pleural mesothelioma. With this method, doctors can remove tissue samples from the chest to look at them under a microscope and identify cancer cells.
  • Thoracotomy: By opening up the chest cavity, doctors can inspect the tissues in greater detail and remove samples to observe them under a microscope.

Histology and Cytology for Pleural Mesothelioma

Histology and cytology are the fields of testing tissue and fluid samples respectively for diseases. Once the tissue and fluid samples are collected from the patient’s chest, they are sent to a pathology lab, where a pathologist examines them.

For tissue samples, pathologists look at them under a microscope to identify any abnormal cells. Different cancer cell types behave differently. Their appearance and behavior can help experienced pathologists make a pleural mesothelioma diagnosis.

Common Pleural Mesothelioma Misdiagnoses

Unfortunately, pleural mesothelioma is commonly misdiagnosed. Early symptoms are often vague and doctors may mistake them for more common conditions that are nonlife-threatening.

Some of the possible conditions that pleural mesothelioma may be mistaken for include:

  • Bronchitis
  • Pneumonia
  • Emphysema
  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Adenocarcinoma and other carcinomas or sarcomas of the lungs (cancer types)

Pleural Mesothelioma Misdiagnosis Update

Another way that pleural mesothelioma is misdiagnosed is either by cell type and/or stage. There are three types of mesothelioma tumors—epithelioid, sarcomatoid and mixed. Doctors may identify only one cell type when the patient actually has mixed cell type (both epithelioid and sarcomatoid cell types).

When diagnosing pleural mesothelioma, doctors also stage the disease so that they know how far it has spread and which treatments to use. Inexperienced doctors who aren’t familiar with how mesothelioma spreads may diagnose pleural mesothelioma at a higher stage than it actually is. Misdiagnoses in either cell type or stage can limit the treatment options available to patients and ultimately shorten their life expectancy.

Second Opinions From Pleural Mesothelioma Specialists

All patients should seek the second opinion of a highly experienced pleural mesothelioma specialist, who can accurately diagnose your disease stage and cell type.

Some of the top pleural mesothelioma specialists available for consultation with include:

If you’ve been diagnosed with pleural mesothelioma, or you suspect you may have symptoms, then contact our Patient Advocates today. Mesothelioma Help Now has a team of dedicated professionals who are here to answer any questions you have about the next steps to take with your diagnosis.

View Author and Sources

  1. Journal of Thoracic Disease: “The continual search for ideal biomarkers for mesothelioma: the hurdles.” Retrieved from: Accessed on December 28, 2017.
  2. Annals of Translational Medicine, Perspective on malignant pleural mesothelioma diagnosis and treatment.” Retrieved from: Accessed on December 28, 2017.
  3. American Cancer Society, “How is Malignant Mesothelioma Diagnosed?” Retrieved from: Accessed on December 28, 2017.
  4. Frontiers in Genetics, “Tumors that mimic asbestos-related mesothelioma: time to consider a genetics-based tumor registry?” Retrieved from: Accessed on December 28, 2017.

Last modified: May 7, 2018