Types of mesothelioma

There are different types of mesothelioma. Here we provide information about pleural mesothelioma, and peritoneal mesothelioma, as well as rarer types.

The mesothelium

Mesothelioma is a cancer of the mesothelium. This is a thin lining (membrane) that covers the outer surface of many organs in the body. It also lines the spaces (cavities) within the body, such as the chest and abdominal cavity.

The mesothelium has different names depending on where it is in the body. For example:

  • the mesothelium in the chest is called the pleura
  • the mesothelium in the tummy (abdomen) is called the peritoneum.

Cancer of the mesothelium is called malignant mesothelioma. But it is usually called mesothelioma.

Mesothelioma in the chest is called pleural mesothelioma. Mesothelioma in the tummy is called peritoneal mesothelioma. Pleural mesothelioma is much more common than peritoneal mesothelioma.

Pleural mesothelioma

The lungs sit within the chest, on either side of the heart. They take in air and supply oxygen to the organs and tissues of the body.

The lungs are covered by a lining (membrane) called the pleura, which has 2 layers. The inner layer covers the lungs. The outer layer lines the ribcage and a sheet of muscle called the diaphragm. The diaphragm separates the chest from the tummy.

Between the 2 layers, in a space called the pleural cavity, is a small amount of fluid. This fluid acts as a lubricant. It allows the lungs to move in and out smoothly and helps you to breathe easily.

Mesothelioma in the pleura starts as tiny lumps (nodules) that are usually spread throughout the pleura. These eventually grow together, causing the layers of the pleura to become thicker. This means the lungs and chest cannot move as freely, causing you to feel breathless.

Fluid may also collect between the 2 layers of the pleura. This is called a pleural effusion.

 

Structure of the lungs and pleura
Image: Structure of the lungs and pleura

 

We have more information about staging and symptoms of pleural mesothelioma.

Peritoneal mesothelioma

The organs in the tummy (abdomen) are covered by a lining (membrane) called the peritoneum. It has an inner and outer layer. The inner layer covers the organs in the abdomen. The outer layer lines the abdominal wall.

The peritoneum helps protect the organs in the abdomen and keeps them in place. When mesothelioma develops in the peritoneum, it causes the layers of the peritoneum to thicken. Fluid may also collect between the 2 layers. This is called ascites.

 

Side view of the tummy (abdomen) showing the peritoneum
Image: Side view of the tummy (abdomen) showing the peritoneum

 

We have more information about staging and symptoms of peritoneal mesothelioma.

Cell types of mesothelioma

Pleural and peritoneal mesothelioma can be grouped by how the cells look under a microscope. The main types are:

  • epithelioid – this is the most common type
  • sarcomatoid
  • mixed or biphasic – this has both epithelioid and sarcomatoid cells
  • cystic and papillary – these are rare and slow growing types of peritoneal mesothelioma.

Knowing the type of cell involved may give your doctors more information about:

  • the best treatment for you
  • how the mesothelioma may respond to treatment.

Rare types of mesothelioma

Very rarely, mesothelioma may develop in the outer lining of other organs. This includes the heart (pericardial mesothelioma) or the testes (testicular mesothelioma).

About our information

  • References

    Below is a sample of the sources used in our mesothelioma information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Woolhouse I et al. British Thoracic Society Guideline for the investigation and management of malignant pleural mesothelioma. Thorax. 2018.

    Thomas A et al. Mesothelioma. BMJ Best Practice. 2019.

    Baas P et al. Malignant pleural mesothelioma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up.  Annals of Oncology. 26 (Supplement 5): v31–v39. 2015. Available from: www.pubmed.ncbi.nlm.nih.gov/26223247

    Kusamara S et al. Peritoneal mesothelioma: PSOGI/EURACAN clinical practice guidelines for diagnosis, treatment and follow-up. European Journal of Surgical Oncology. March 2020.


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr David Gilligan, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.