What Is Mesothelioma?

Definition, Symptoms, Treatment, and Prevention

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Mesothelioma is a somewhat rare cancer, with only about 2,000 new cases diagnosed in the United States each year—but its incidence is increasing worldwide. Sadly, most cases of this disease are related to on-the-job exposure to asbestos and could be prevented through awareness and protective measures at work. That said, in many cases, mesothelioma does not develop until decades after asbestos exposure occurs, and many people that are diagnosed today were exposed to asbestos years ago.

Types of Mesothelioma

Mesothelioma is a cancerous (malignant) tumor that begins in the mesothelium. The mesothelium is a membrane that lines and protects the lungs, the heart, and the abdominal cavity. There are three main types of mesothelioma.

  1. Pleural mesothelioma begins in the pleura (the lining of the lungs). This is the most common type of mesothelioma.
  2. Peritoneal mesothelioma begins in the peritoneum (the lining of the abdominal cavity).
  3. Pericardial mesothelioma begins in the pericardium (the lining of the heart).
Symptoms of pleural mesothelioma
Illustration by JR Bee, Verywell 

Mesothelioma Symptoms

Most people with pleural mesothelioma note shortness of breath and chest pain (especially under the ribs), but there are several other symptoms including:

  • Pain in the shoulder, chest or lower back (in one study, shoulder pain was the first symptom of pleural mesothelioma in 14 percent of patients)
  • Shortness of breath
  • Cough
  • Trouble swallowing (feeling like food is getting stuck in your throat)
  • Hoarseness
  • Swelling of the face and arms
  • Unexplained weight loss or night sweats
  • Fatigue  

In addition, blood clots usually develop with more advanced pleural mesothelioma. On the other hand, with peritoneal mesothelioma, abdominal pain and bloating is a common symptom.


There are several contributing factors that have been linked to the development of mesothelioma. On-the-job exposure to asbestos has often been linked to mesothelioma. In addition, some people are more likely to develop mesothelioma than others due to genetic predisposition. Exposure to a virus called simian virus 40 (SV 40) has been linked with some cases of mesothelioma. Exposure to radiation has also been linked to mesothelioma.


Diagnosing mesothelioma can be difficult since there are many conditions that cause similar symptoms. Your healthcare provider will first take a careful history, especially questioning you about your employment history, and then perform a physical exam. Imaging studies are often done and may include x-rays of your chest and abdomen, CT scans, MRI scans, or PET scans.

If your healthcare provider suspects mesothelioma, she will need to schedule a biopsy. Depending upon the location of your tumor, she may recommend a thoracoscopy or video-assisted thoracoscopy (VAT), a procedure where a tissue sample is taken from the pleura, or a peritoneoscopy, a similar procedure to obtain tissue from the abdomen. If the biopsy reveals mesothelioma, further studies are then done to determine the stage of the cancer (how advanced it is).


Mesothelioma is divided into 2 primary stages:

  • Localized (Stage 1). With localized mesothelioma, the cancer is confined to the mesothelium—the pleura with pleural mesothelioma, or the peritoneum with peritoneal mesothelioma.
  • Advanced (Stage 2, 3, and 4). Mesothelioma is considered advanced if it has spread to the lymph nodes or other organs including the lungs.


Depending on the size and location of your tumor, and if it has spread, treatment may include one of several options.

Treatments for Mesothelioma

  1. Surgery
  2. Chemotherapy
  3. Radiation Therapy
  4. Clinical Trials
  • In certain cases, surgery may be considered, especially if the tumor is caught at an early stage. Types of surgery for mesothelioma include a pleurectomy, during which a portion of the pleura is removed. Another type is an extrapleural pneumonectomy, during which a portion of the pleura is removed as well as a portion of the pericardium (heart lining), diaphragm (muscle separating the chest and abdomen) and the lung.
  • Another common treatment is a combination of chemotherapy along with targeted therapy, which may improve the chances of survival. 
  • Radiation therapy is sometimes used as a type of palliative treatment for mesothelioma. Though this kind of treatment does not cure cancer, it can make you more comfortable. It may also be used after surgery to kill any remaining cancer cells.
  • Finally, several clinical trials are in progress and evaluating new ways to treat mesothelioma.


On top of the emotional toll that accompanies a cancer diagnosis, many people with mesothelioma lack the emotional and psychosocial support that those with other forms of cancer may find readily available. In addition, medico-legal battles related to on-the-job asbestos exposure can be emotionally draining. Participating in a support group, either through your cancer center, community, or online, can help you wade through the maze of treatment options, and find camaraderie in others who are living with mesothelioma.


The most important thing you can do to prevent mesothelioma is to use appropriate precautions if you are exposed to asbestos at work.

OSHA has asbestos safety standards for individuals who may be exposed on the job. If you work with asbestos, it is important to follow these guidelines to minimize your families exposure as well. Asbestos insulation in homes is usually not a problem unless it is damaged or disturbed by remodeling projects. If you may have asbestos insulation (homes built prior to 1950) make sure to hire a contractor certified in asbestos management before you begin any home improvement projects.

Some people who have been exposed to asbestos may want to consider CT screening for lung cancer. At this time, recommendations for screening include only those people ages 55 to 74 with a 30 pack-per-year history of smoking.

Yet studies show that some people who have been exposed to asbestos may be at an even higher risk of developing lung cancer than heavy smokers. If you've been exposed to asbestos make sure to talk to your healthcare provider about lung cancer screening.

A Word From Verywell

Mesothelioma, though considered a somewhat rare cancer, is becoming increasingly common worldwide. If you are experiencing symptoms of mesothelioma, especially if you have had or suspect that you've had previous exposure to asbestos, speak with your doctor or healthcare professional. If diagnosed with mesothelioma, it is key to form a support group of either family or friends, or to become involved with a supportive cancer community online. This can provide you with a network of people who are going through similar situations and can help you to navigate treatment options.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."