Table Of Contents

What Is the Mesothelium?

The mesothelium is a layer of cells that covers and protects organs and tissue in the body. It also helps regulate response to injury, infection and disease.

Research suggests that it may have other functions, as well. The mesothelium may play a role in transporting fluid and controlling inflammation.

The mesothelium goes by different names depending upon the parts of the body it covers.

  • The pleura covers the lungs and chest wall
  • The peritoneum covers the abdominal organs and abdominal wall
  • The pericardium covers the heart
  • The tunica vaginalis covers the testes
What Diseases Affect the Mesothelium? Pleural Diseases: The pleura covers the lungs and chest wall. Peritoneal Diseases: The peritoneum covers the abdominal organs and abdominal wall. Pericardial Diseases: The pericardium covers the heart. Tunica Vaginalis Diseases: The tunica vaginalis covers the testes.

Asbestos can harm the mesothelium. Once inhaled or ingested, the toxic fibers become stuck. Over time, they irritate cells and tissue.

Research suggests that the lymphatic system may play a role. Fibers may travel to the mesothelium with help from the lymph system.

Asbestos exposure can cause mesothelioma and other asbestos-related diseases in the mesothelium.

Mesothelium Structure and Function

The mesothelium is made up of two layers.

  • The visceral layer covers the organ
  • The parietal layer covers the body cavity

Mesothelial cells comprise these layers. These cells are a type of epithelial cell. They appear flat and squamous-like.

Quick Fact:
The mesothelium is a slowly renewing tissue. Less than 1% of the cells undergo cell division at any one time.

The primary function of the mesothelium is to provide a protective surface. This surface is flexible and not restrictive of the organs it covers.

Other functions of the mesothelium include:

  • Transporting fluids and cells
  • Inflammation and tissue repair
  • Protection against invading microorganisms
  • Presenting antigens (immune proteins) to lymphocytes (immune cells)
  • Blood clotting to heal wounds
  • Tumor cell adhesion to prevent cancerous spreading
mesothelioma guide
Get a Free Mesothelioma Guide
Learn about your diagnosis, top doctors and how to pay for treatment.

Diseases of the Mesothelium

Cancer can develop in the mesothelium after inflammation and scarring. If the damage does not heal, the mesothelium can develop fibrous adhesions. These changes in mesothelial cells lead to malignant mesothelioma and other cancers.

Effusions are the accumulation of fluid between the layers of the mesothelium. They can develop as a result of inflammation and cancer in the mesothelium. Effusions are a symptom of mesothelial diseases. They are not a primary condition.

Pleural Diseases

Benign and cancerous diseases of the pleura can develop as a result of asbestos exposure.

  • Pleuritis is inflammation of the pleura.
  • Pleural plaques are fibrous scar tissue on the pleura that may become calcified.
  • Pleural thickening is extensive scarring that thickens and restricts the pleura.
  • Atelectasis is a contraction of pleural scar tissue that folds the pleura into the lung. This causes the lungs to underinflate.
  • Pleural mesothelioma is cancer of the pleura.

Peritoneal Diseases

Benign and cancerous diseases can also develop in the peritoneum.

  • Peritonitis is inflammation of the peritoneum.
  • Peritoneal mesothelioma is cancer of the peritoneum.
  • Primary peritoneal serous carcinoma is another cancer of the peritoneum.

Asbestos exposure is the primary cause of peritoneal mesothelioma. Inflammation of the peritoneum is peritonitis. Bacterial or fungal infections are the most common causes.

Primary peritoneal serous carcinoma is a type of cancer that can also occur in this area. A 2022 study likened it to advanced-stage serous ovarian carcinoma.

Pericardial Diseases

Several benign conditions and cancers can develop in the pericardium.

  • Pericarditis is inflammation of the pericardium.
  • Cardiac tamponade is compression of the heart by fluid accumulation.
  • Pericardial constriction is scarring and a loss of elasticity of the pericardium.
  • Pericardial mesothelioma is cancer of the pericardium.
  • Several other cancers can develop in the pericardium, including sarcomas, lymphoma and primitive neuroectodermal tumor.

Tunica Vaginalis Diseases

Benign and cancerous diseases can develop in the tunica vaginalis.

  • Hydrocele is an abnormal amount of fluid between the layers of the tunica vaginalis.
  • Scrotal calculi are calcified deposits that form between the layers of the tunica vaginalis.
  • Fibrous pseudotumors are benign lesions of the tunica vaginalis.
  • Testicular mesothelioma is cancer of the tunica vaginalis.
  • Several other cancers can develop in the tunica vaginalis including mesenchymal tumors, lymphomas and serous borderline tumors.
  • A few benign tumors can develop as well, including adenomatoid tumor, scrotal tunica cyst, lipoma and leiomyoma.

The mesothelium plays an important role in protecting organs and responding to inflammation, injury and disease.

Make an appointment with your doctor if you have a history of asbestos exposure and develop abnormal symptoms affecting the lungs, abdomen, heart or testes.

lawyers standing together
Get the Compensation You Deserve
open view of mesothelioma guide and cover
The Nation's Top Mesothelioma Guide
scientists in laboratory
Immunotherapy & Mesothelioma Clinical Trials