Mesothelioma: The Basics

Author: Christina Bach, MBE, LCSW, OSW-C, FAOSW
Content Contributor: Allyson Distel, MPH
Last Reviewed: January 16, 2024

Mesothelioma is caused by mesothelial cells growing out of control. The mesothelium is a protective sac. It covers organs inside the body such as:

  • Stomach organs.
  • Lungs.
  • Male sex glands.
  • Heart.

When these cells grow out of control, they can no longer stop making lubricating fluid. This fluid helps the organs move smoothly. This turns into extra fluid and a tumor.

Mesothelioma that has spread to some other part of the body from its first site is called metastatic cancer.


The biggest risk is having been around asbestos. Mesothelioma may not be found until many years after you were near asbestos. Your risk for mesothelioma is higher if you smoke or have smoked. Other risks are:

  • Radiation to the chest.
  • Some viruses or certain minerals (erionite).
  • About 1 out of 100 cases of mesothelioma are caused by changes to your genes.


There are no standard tests to screen for mesothelioma.

Signs of Mesothelioma

The first sign of mesothelioma of the lungs is having pain and a hard time breathing. Other signs are:

  • Weight loss.
  • Dry, hacking cough.

Signs of mesothelioma of the belly:

  • Belly swelling.
  • Bowel obstruction (block).
  • Pain.
  • Weight loss.

Diagnosis of Mesothelioma

If you start to have signs of mesothelioma, tests will be ordered:

  • X-ray.
  • CT scan.
  • A test to check the fluid around your lungs. This is called a thoracentesis.
  • A test where you take a small group of cells to check for cancer. This is also called a biopsy. 

Staging Mesothelioma

To make a treatment plan, mesothelioma of the lungs is "staged." The stage is based on:

  • Size and where the tumor is.
  • If cancer is found in the lymph nodes.
  • If cancer is found in other parts of the body.

Stages range from stage I to stage IV. There is no standard staging for other types of mesothelioma.


Treatment depends on the stage, where it is, and the person’s health. Choices can be:

This is a basic article about mesothelioma. You can learn more about mesothelioma by using the links below.

Surgical Procedures: Surgery and Staging for Malignant Mesothelioma

Mesothelioma: Staging and Treatment

American Cancer Society (2018). Malignant Mesothelioma Stages

 American Society of Clinical Oncology (2020). Mesothelioma Risk Factors.

American Society of Clinical Oncology (2020). Mesothelioma: Symptoms and Signs. 

National Comprehensive Cancer Network (2023). Mesothelioma: Pleural. 

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