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Find Your CenterMesothelial cells line the body's internal organs. They protect organs and help balance fluids. Pathologists examine these cells to diagnose diseases like mesothelioma. They can be normal, reactive or malignant.
Mesothelial cells are special cells that line the outside of your lungs, heart and abdominal organs. This is the type of cell where mesothelioma cancer starts. Mesothelial cells form a protective layer and prevent friction between organs. They’re involved in tissue repair and inflammation response.
Key Facts About Mesothelial Cells
These cells also produce a slippery fluid that acts like a lubricant. It allows organs to slide against each other as you breathe or move.
When these cells become cancerous, they produce too much fluid. This excess fluid can compress the lungs and make it hard to breathe. Learning about these cells helps you understand the disease.
Mesothelial cells can undergo reactive, atypical or malignant changes. These changes can range from normal reactions to irritation to cancerous transformations.
Understanding these changes is important for diagnosing mesothelioma. Asbestos exposure is a major cause of serious mesothelial cell changes.
Types of Mesothelial Cell Changes
Some changes, like reactive or floridly reactive changes, are often simply the body’s response to irritation. Malignant changes mean the cells are cancerous, as seen in malignant mesothelioma. It’s crucial to identify the different types of changes to properly diagnose and treat related diseases.
Floridly reactive changes aren’t cancer and are different from mesothelioma. These pronounced changes often happen because the cells are reacting to something that’s bothering them.
They might be larger than normal mesothelial cells or have some other unusual features. While they can look abnormal under a microscope, floridly reactive cells are usually a sign your body is trying to heal or respond to a problem.
Malignant mesothelial cell changes mean the cells have become cancerous. These cells grow uncontrollably and can spread to other parts of the body. This is what happens with mesothelioma.
The main cause of malignant mesothelial cell changes is asbestos exposure. It’s very different from a normal reaction to irritation.
Reactive mesothelial cell changes might look a little different than usual, but they’re not necessarily cancerous. For mesothelioma patients, reactive changes can sometimes be confusing. They might look like cancerous changes.
It’s important for doctors to carefully examine the cells to tell the difference and make the correct diagnosis. These changes could mean the cells are responding to some kind of stimulus. This could be inflammation, injury or irritation. Many things can cause reactive changes. Infections, fluid buildup and surgery can irritate the mesothelial cells.
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Find Your CenterMesothelial cells are naturally found in pleural fluid, which is a thin layer of liquid surrounding your lungs. These cells play an important role in keeping the lungs healthy. Cancers like pleural mesothelioma can develop in these cells, affecting your body’s fluid levels.
Sometimes, too much fluid builds up in the pleural space, causing what’s known as a pleural effusion. Peritoneal mesothelioma can also cause fluid buildup. This is known as a peritoneal effusion or ascites.
Functions of Mesothelial Cells in Pleural and Peritoneal Fluid
It’s normal to have some mesothelial cells in pleural and peritoneal fluid, but a large increase in these cells can sometimes be a sign of a problem. For example, a very high number of mesothelial cells might suggest inflammation. It could even be a sign of cancers like pleural or peritoneal mesothelioma.
Doctors look at the number and appearance of these cells, along with other tests, to figure out what’s going on. An excessive amount is more than what’s typically found in a healthy person, but the exact number can vary.
Symptoms may include chest or abdominal pain and coughing. This cancer most often affects the lining of the lungs or abdomen. Mesothelioma symptoms can vary depending on where the cancer develops. It’s important to see a doctor if you have any concerning symptoms.
Symptoms Associated With Malignant Mesothelial Cells
Other illnesses can also cause these symptoms. If you have a history of asbestos exposure, it’s important to talk to your doctor about any symptoms you’re experiencing. Early diagnosis is important for mesothelioma. It can help improve your treatment outcomes.
One of the most important diagnostic tests is a biopsy. A biopsy involves taking a small sample of tissue. Diagnosing malignant mesothelial cells can be tricky. Doctors use a combination of tests to figure out what’s going on.
For a mesothelioma biopsy, doctors might use a needle to take a sample of fluid or tissue from around the lungs or abdomen. Sometimes, they need to do a more involved procedure to get a good enough sample. This might involve minor surgery. The tissue sample is then sent to a lab.
At the lab, specially trained doctors called pathologists look at the cells under a microscope. They’re searching for specific changes that would indicate malignant mesothelial cells. This is how mesothelioma is diagnosed. These changes can be difficult to spot, so it’s important that the pathologist is experienced in diagnosing mesothelioma.
Malignant mesothelial cells are commonly treated with chemo and other anti-cancer therapies. They’re a sign of serious disease, most often mesothelioma. Treating these cells means treating the underlying disease.
Because mesothelioma is a cancer, treatment focuses on getting rid of the cancerous cells and preventing them from spreading. Mesothelioma treatment can be complex and depends on several factors.
Most Common Treatments for Malignant Mesothelial Cells
Mesothelioma treatment often involves a combination of these approaches. Doctors will work with patients to create a treatment plan that’s right for them.
It’s important for mesothelioma patients to talk to their doctors about all their treatment options and any concerns they may have. Clinical trials are also an option for some patients, offering access to newer treatments.
Early warning signs of malignant mesothelial cells can be vague. They might include chest pain, shortness of breath or abdominal swelling.
Sometimes, there are no noticeable symptoms at all in the early stages. Because mesothelioma is often linked to asbestos exposure, anyone with that history should be aware of any unusual symptoms.
Yes, malignant mesothelial cells can spread to other organs. This process is called metastasis. Mesothelioma can spread to nearby tissues and lymph nodes.
In later stages, it can spread to distant organs. Distant spreading makes the disease harder to treat.
Mesothelial cells have some ability to repair themselves after minor damage. If the damage is severe or ongoing, like from asbestos exposure, the cells can become abnormal and eventually cancerous. This is why mesothelioma is a serious and life-threatening disease.
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Selby, K. (2026, February 13). Mesothelial Cells. Asbestos.com. Retrieved February 23, 2026, from https://www.asbestos.com/mesothelioma/cells/mesothelial/
Selby, Karen. "Mesothelial Cells." Asbestos.com, 13 Feb 2026, https://www.asbestos.com/mesothelioma/cells/mesothelial/.
Selby, Karen. "Mesothelial Cells." Asbestos.com. Last modified February 13, 2026. https://www.asbestos.com/mesothelioma/cells/mesothelial/.
Dr. Velotta is a leading thoracic surgeon and pleural mesothelioma specialist at Kaiser Permanente Oakland Medical Center and a Clinical Assistant Surgical Professor at the University of California, San Francisco School of Medicine. With more than 15 years of experience, he leads research efforts in minimally invasive lung cancer surgery, pain management post-thoracic surgery and multimodal mesothelioma treatment. He is recognized for advancing image-guided surgical techniques and improving regional access to specialized mesothelioma care.
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