Skip Navigation

General Information About Malignant Mesothelioma

Malignant mesothelioma is a disease in which malignant (cancer) cells form in the lining of the chest or abdomen.

Malignant mesothelioma is a disease in which malignant (cancer) cells are found in the pleura (the thin layer of tissue that lines the chest cavity and covers the lungs) or the peritoneum (the thin layer of tissue that lines the abdomen and covers most of the organs in the abdomen). Malignant mesothelioma may also form in the heart or testicles, but this is rare.

Being exposed to asbestos can affect the risk of malignant mesothelioma.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk to your doctor if you think you may be at risk.

Most people with malignant mesothelioma have worked or lived in places where they inhaled or swallowed asbestos. After being exposed to asbestos, it usually takes a long time for malignant mesothelioma to form. Living with a person who works near asbestos is also a risk factor for malignant mesothelioma.

Signs and symptoms of malignant mesothelioma include shortness of breath and pain under the rib cage.

Sometimes the cancer causes fluid to collect in the chest or in the abdomen. Signs and symptoms may be caused by the fluid, malignant mesothelioma, or other conditions. Check with your doctor if you have any of the following:

  • Trouble breathing.
  • Cough.
  • Pain under the rib cage.
  • Pain or swelling in the abdomen.
  • Lumps in the abdomen.
  • Constipation.
  • Problems with blood clots (clots form when they shouldn’t).
  • Weight loss for no known reason.
  • Feeling very tired.

Tests that examine the inside of the chest and abdomen are used to detect (find) and diagnose malignant mesothelioma.

Sometimes it is hard to tell the difference between malignant mesothelioma in the chest and lung cancer.

The following tests and procedures may be used to diagnose malignant mesothelioma in the chest or peritoneum:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits, exposure to asbestos, and past illnesses and treatments will also be taken.
  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of the chest and abdomen, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
  • Biopsy: The removal of cells or tissues from the pleura or peritoneum so they can be viewed under a microscope by a pathologist to check for signs of cancer.

    Procedures used to collect the cells or tissues include the following:

    • Fine-needle (FNA) aspiration biopsy of the lung: The removal of tissue or fluid using a thin needle. An imaging procedure is used to locate the abnormal tissue or fluid in the lung. A small incision may be made in the skin where the biopsy needle is inserted into the abnormal tissue or fluid, and a sample is removed.
    • Thoracoscopy: An incision (cut) is made between two ribs and a thoracoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted into the chest.
    • Thoracotomy: An incision (cut) is made between two ribs to check inside the chest for signs of disease.
    • Peritoneoscopy: An incision (cut) is made in the abdominal wall and a peritoneoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted into the abdomen.
    • Open biopsy: A procedure in which an incision (cut) is made through the skin to expose and remove tissues to check for signs of disease.

    The following tests may be done on the cells and tissue samples that are taken:

    • Cytologic exam: An exam of cells under a microscope to check for anything abnormal. For mesothelioma, fluid is taken from the chest or from the abdomen. A pathologist checks the fluid for signs of cancer.
    • Immunohistochemistry: A laboratory test that uses antibodies to check for certain antigens (markers) in a sample of a patient’s tissue. The antibodies are usually linked to an enzyme or a fluorescent dye. After the antibodies bind to a specific antigen in the tissue sample, the enzyme or dye is activated, and the antigen can then be seen under a microscope. This type of test is used to help diagnose cancer and to help tell one type of cancer from another type of cancer.
    • Electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under a high-powered microscope to look for certain changes in the cells. An electron microscope shows tiny details better than other types of microscopes.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

  • The stage of the cancer.
  • The size of the tumor.
  • Whether the tumor can be removed completely by surgery.
  • The amount of fluid in the chest or abdomen.
  • The patient's age.
  • The patient's activity level.
  • The patient's general health, including lung and heart health.
  • The type of mesothelioma cells and how they look under a microscope.
  • The number of white blood cells and how much hemoglobin is in the blood.
  • Whether the patient is male or female.
  • Whether the cancer has just been diagnosed or has recurred (come back).
This information is not intended to replace the advice of a doctor. Navigating Care disclaims any liability for the decisions you make based on this information. This information was sourced and adapted from Adapted from the National Cancer Institute's Physician Data Query (PDQ®) Cancer Information Summaries on www.cancer.gov.

See Expert Resources

The Navigating Care Library includes articles about cancer, chemotherapy regimens and drugs from the the National Cancer Institute and other experts.

Specific Facts for Your Diagnosis

Learn about treatment options and managing side effects from experts.

Get Support on Your Cancer Journey

Connect with thousands of members with your diagnosis and learn from their experiences.