Mesothelioma, or malignant mesothelioma, is a rare kind of cancer. It starts in the mesothelium, a thin lining that protects the outer surface of some organs, including the lungs, stomach/abdominal space and chest wall. The mesothelium also makes fluid that helps the organs move against each other during certain processes, such as breathing. The mesothelium has different names for different body parts:

  • The lining in the chest is the pleura.
  • The lining in the abdomen is the peritoneum.

Mesothelioma can start in any of these linings. It’s most common in the chest, where it’s called pleural mesothelioma. The second most common site is the abdomen, where it’s called peritoneal mesothelioma.


Mesotheliomas can be categorized based on how the cancer cells look under a microscope.

  • The epithelioid mesothelioma is the most common. It also tends to have a better outlook than the other types.
  • The sarcomatoid mesothelioma tends to be harder to treat.
  • The mixed (biphasic) mesothelioma has both epithelioid and sarcomatoid areas. It tends to have an outlook that falls between the other two types.


Exposure to asbestos is the most common cause of mesothelioma. However, most people who are exposed to large amounts of asbestos do not get mesothelioma. 

Some studies indicate that radiation treatment for other cancers have been linked to mesothelioma.


Unlike many other cancers, mesothelioma typically does not grow as a single, large tumor. Instead, it often starts growing along the organ’s lining. This can affect how well the lining works, which can result in symptoms. Mesothelioma often does not cause symptoms in its early stages. Symptoms depend on where the cancer is located and may not develop until the cancer advances.

Pleural mesothelioma (in the chest) can cause symptoms that include:

  • Breathing problems, such as shortness of breath, often related to fluid accumulation around the lung(s)
  • Coughing
  • Chest pain
  • Fever
  • Difficulty swallowing
  • Weight loss
  • Fatigue
  • Hoarseness

Peritoneal mesothelioma (in the abdomen) can cause symptoms that include:

  • Pain in your belly
  • Swelling or fluid in your belly
  • Weight loss
  • Nausea or vomiting
  • Constipation
  • Fever
  • Fatigue

Diagnosing Mesothelioma

Your doctor will ask about your health history, symptoms, risk factors and family history of disease. You can also expect a physical exam. You may have a combination of imaging tests, blood tests and a biopsy (tissue sample).

  • Chest X-ray: shows fluid or other signs of cancer in the spaces around your lungs
  • CT scan: shows more detailed imaged of your chest or abdomen than an X-ray
  • PET scan: uses a special camera and glucose (sugar) that carries a radioactive substance to help detect cancer cells
  • Biopsy: examines tissue sample for cancer cells
  • Thoracoscopy: uses a thin tube with a camera (thoracoscope) to view the tumor through your chest wall
  • Laparoscopy: uses a thin tube with a camera (laparoscope) to view the tumor through your belly
  • Bronchoscopy: uses a thin tube (bronchoscope) to view tumors in the airways
  • Thoracotomy: a procedure during which a doctor makes a larger incision in your chest to remove a larger piece of tissue from the tumor or the entire tumor (occasionally the best way to diagnose mesothelioma)
  • Laparotomy: a procedure during which a doctor makes a larger incision in your abdomen to remove a larger piece of tissue from the tumor or the entire tumor
  • Thoracentesis, pericardiocentesis and paracentesis: a procedure during which a doctor uses a long, hollow needle to remove fluid from your chest, sac around your heart or abdomen


Mesothelioma is commonly treated with a combination of the following.

  • Chemotherapy: With chemotherapy, medications are used to kill cancer cells via the bloodstream. Different chemotherapy drugs destroy cancer cells by a variety of different mechanisms. If surgery is appropriate, chemotherapy can help kill any remaining mesothelioma cells.
  • Radiation therapy: Radiation therapy, or radiation oncology, involves using targeted, penetrating rays of energy (radiation) to destroy cancer cells. Radiation can shrink mesothelioma tumors, making them easier to be surgically removed. Depending on the location, radiation can be delivered by an external or an internal source.
  • Surgery: Surgery can be used to remove all or most of early stage tumors. Depending on the location, surgery may include removing the lining, lymph node(s), or part or all of the lung or other affected organ.