Mesothelioma Overview
Mesothelioma: Symptoms, Causes, Diagnosis and Treatment
Mesothelioma is a rare cancer that begins in the mesothelium, the thin layer of tissue that lines several body cavities and covers certain organs. Asbestos is the major established risk factor for mesothelioma, but an exposure history is not the same as a diagnosis.
Mesothelioma is a rare cancer that begins in the mesothelium, the thin layer of tissue that lines several body cavities and covers certain organs. Most cases start in the pleura around the lungs. Less often, mesothelioma begins in the peritoneum in the abdomen; pericardial and tunica vaginalis mesotheliomas are very rare.
Asbestos is the major established risk factor for mesothelioma, but an exposure history is not the same as a diagnosis. Many people who were exposed never develop the disease, and some patients do not recall a clear exposure. Symptoms can also resemble far more common conditions, which is why diagnosis usually depends on imaging followed by pathologic evaluation of cells or tissue.
If you are trying to understand a new diagnosis, a possible diagnosis, or a past asbestos exposure, this page gives the clinical overview first and then directs you to the more detailed guides.
Start Here: Understanding Mesothelioma
People often arrive here with several questions at once. It helps to separate them: what mesothelioma is, how it is diagnosed, what treatment may involve, and what an asbestos history does or does not tell us.
01Understand
02Recognize
03Get Answers
What Is Mesothelioma?
Malignant mesothelioma is a cancer of mesothelial tissue. The name tells us where the cancer begins; it does not describe one uniform disease. A pleural mesothelioma and a peritoneal mesothelioma arise from related tissue, but they are evaluated, staged, and treated differently.
Pleural mesothelioma is the most common form and begins in the pleura, the lining of the chest cavity and surface of the lungs. Peritoneal mesothelioma begins in the abdominal lining. Pericardial mesothelioma arises in the sac around the heart, and tunica vaginalis mesothelioma develops in the membrane surrounding the testis.
Pathology adds another layer of information. Pleural mesothelioma is commonly described as epithelioid, biphasic, or sarcomatoid, and histology can influence prognosis and treatment discussions.
Types of Mesothelioma
| Type | Where it begins | What patients may notice |
|---|---|---|
| Pleural mesothelioma | Pleura – lining of the chest cavity and lungs | The most common form. Symptoms may include shortness of breath, chest discomfort, cough, or pleural effusion, but none of these findings is specific to mesothelioma. |
| Peritoneal mesothelioma | Peritoneum – lining of the abdomen | May cause abdominal swelling or pain, digestive symptoms, reduced appetite, or unexplained weight loss. |
| Pericardial mesothelioma | Pericardium – sac around the heart | Exceptionally rare. Symptoms can overlap with other cardiac or pericardial conditions. |
| Tunica vaginalis mesothelioma | Tunica vaginalis – membrane surrounding the testis | Very rare. It may be discovered during evaluation of a scrotal mass, swelling, hydrocele, or another local problem. |
The anatomical type is not just a label. It affects which specialists are involved, how disease extent is described, and which treatments have evidence for that particular site.
From Symptoms to Diagnosis
Mesothelioma rarely announces itself with one distinctive symptom. Shortness of breath, chest pain, abdominal swelling, fatigue, cough, and weight loss can all occur for many other reasons. The diagnosis is therefore built step by step rather than inferred from symptoms or an asbestos history alone.
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Clinical history and examination. A clinician reviews the symptoms, general health, previous illnesses, and any known occupational, household, or environmental asbestos exposure.
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Imaging. Chest x-ray, CT, PET/CT, MRI, or other imaging may identify pleural, abdominal, or other abnormalities and help determine where further testing or sampling is needed.
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Fluid or tissue sampling. Fluid cytology can provide useful information in some cases, but it may not be sufficient to establish mesothelioma. Tissue biopsy is frequently needed when the diagnosis remains suspected.
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Pathology. A pathologist examines cells or tissue and uses morphology together with immunohistochemical markers to distinguish mesothelioma from cancers that can look similar.
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Type, histology, and disease extent. Once the diagnosis is established, the care team defines the anatomical type, histologic subtype when applicable, and extent of disease so treatment can be planned appropriately.
How Asbestos Exposure Fits In
Most mesotheliomas are associated with asbestos exposure, and the relationship is especially well established for pleural mesothelioma. Exposure may have occurred at work, through contaminated work clothing brought home by a family member, or from environmental sources.
Risk generally rises with greater cumulative exposure, but an exposure history cannot tell us with certainty who will develop mesothelioma. The reverse is also important: the absence of a remembered asbestos exposure does not rule the disease out.
When clinicians reconstruct an occupational history, the details of the work are often more useful than the job title. Insulation work, ship repair, demolition, maintenance, and work with older friction products or gaskets are examples of tasks that may have involved asbestos.
For more detail, see Asbestos Exposure, Occupational Asbestos Exposure, and Mesothelioma Causes and Risk Factors.
Mesothelioma Treatment and Care
There is no single treatment plan for mesothelioma. The site where the cancer began, disease extent, histology, overall health, symptoms, previous treatment, and the patient’s goals all matter. Because the disease is uncommon and treatment can be complex, decisions are best made with a team experienced in mesothelioma.
| Treatment approach | How it may fit into care |
|---|---|
| Surgery for pleural disease | For highly selected patients with resectable pleural mesothelioma, surgery may be considered as part of a multimodality plan at an experienced center. The role of surgery is individualized and is not appropriate for every patient. |
| Cytoreduction + HIPEC for peritoneal disease | For selected patients with diffuse malignant peritoneal mesothelioma, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) may be offered when disease is confined to the abdomen, performance status is good, and complete or near-complete cytoreduction appears achievable. |
| Chemotherapy | Pemetrexed with a platinum drug remains an important systemic option for pleural mesothelioma and may be used in combination strategies. Evidence for systemic regimens in peritoneal mesothelioma is less robust than in pleural disease. |
| Immunotherapy | Immunotherapy is an established first-line option for unresectable malignant pleural mesothelioma. Nivolumab plus ipilimumab is FDA approved for adults with unresectable malignant pleural mesothelioma. Pembrolizumab with pemetrexed and platinum chemotherapy is FDA approved for first-line treatment of unresectable advanced or metastatic malignant pleural mesothelioma. |
| Radiation therapy | Radiation may be used in selected situations for local control or symptom relief. Its role depends on disease site, previous treatment, and the overall treatment plan. |
| Supportive and palliative care | Symptom management belongs alongside cancer-directed treatment. Care may include management of pain, breathlessness, pleural or abdominal fluid, fatigue, nutrition problems, and the emotional effects of cancer. |
| Clinical trials | Clinical trials are particularly important in a rare cancer where treatment continues to evolve and may provide access to approaches that are not yet standard care. |
A key limitation is that treatment evidence cannot automatically be transferred from one anatomical type to another. For example, the pivotal nivolumab-plus-ipilimumab trials and the FDA approvals above concern pleural mesothelioma; evidence for the same first-line approach in peritoneal mesothelioma is much more limited.
In the five-year follow-up of CheckMate 743, first-line nivolumab plus ipilimumab continued to show an overall-survival benefit over chemotherapy in unresectable pleural mesothelioma. Five-year overall survival was 14% with nivolumab plus ipilimumab and 6% with chemotherapy in the randomized population. These are trial-level results, not a prediction for an individual patient.
Stages and Prognosis
Stage describes the extent of cancer and helps guide treatment. The familiar stage 1 through 4 system used in this site’s staging guides refers to diffuse malignant pleural mesothelioma. Other anatomical forms of mesothelioma are not staged in exactly the same way, so a stage label should always be interpreted in the context of where the cancer began.
Prognosis is also individual. In pleural mesothelioma, factors such as stage, performance status, histology, age, overall health, and whether treatment can be delivered all influence outcomes. Statistics summarize what happened to groups of patients; they cannot tell one person exactly how long they will live.
See the detailed guides on Mesothelioma Stages and Mesothelioma Prognosis.
Why Specialist Care Matters
Mesothelioma is uncommon, and the important decisions are often highly specialized: confirming pathology, interpreting complex imaging, deciding whether surgery has a role, choosing systemic therapy, managing fluid or pain, and considering clinical trials. An experienced mesothelioma team can review the diagnosis and explain which options are realistic for the individual’s type of disease and overall health.
Patient and Family Support
Cancer treatment is only one part of living with mesothelioma. Patients and families may also need help with transportation, finances, caregiving, symptom control, emotional support, work questions, or veterans’ benefits. Those needs can change over time, including when treatment begins, when treatment changes, or when the goals of care shift.
Compensation and Legal Information
People with a history of occupational or environmental asbestos exposure may also have questions about compensation, filing deadlines, veterans’ benefits, or legal representation. Those questions are separate from medical diagnosis and treatment. Eligibility and deadlines depend on the person’s circumstances and the law that applies, so general website information should not be treated as individual legal advice.
Frequently Asked Questions
Is mesothelioma the same as lung cancer?
No. Pleural mesothelioma begins in the mesothelial lining around the lungs and chest, while lung cancer begins in lung tissue. The distinction matters because the pathology, staging, and treatment are different.
Is asbestos the only cause of mesothelioma?
Asbestos is the major established risk factor and is linked to most mesotheliomas, particularly pleural disease. However, some patients have no identified exposure or other known risk factor.
What is the most common type of mesothelioma?
Pleural mesothelioma is the most common form. It begins in the pleura, the tissue lining the chest cavity and covering the lungs.
How is mesothelioma confirmed?
Imaging can show an abnormality and guide the workup, but confirmation depends on pathology. Fluid cytology may help in some cases, yet tissue biopsy is often needed so the pathologist can evaluate the tumor and use immunohistochemical markers when necessary.
Can mesothelioma be cured?
Mesothelioma is often difficult to cure. A small, carefully selected group of patients may undergo aggressive treatment with long-term disease control or curative intent, while many others are treated with the goals of controlling the cancer, relieving symptoms, and extending survival. The answer depends heavily on anatomical type, disease extent, histology, overall health, and specialist assessment.
Is immunotherapy a standard treatment for mesothelioma?
For unresectable malignant pleural mesothelioma, immunotherapy is established first-line treatment. Nivolumab plus ipilimumab is FDA approved, and pembrolizumab with pemetrexed and platinum chemotherapy is also FDA approved for unresectable advanced or metastatic pleural disease. These approvals should not automatically be extrapolated to every anatomical type of mesothelioma.
Does every mesothelioma use stages 1 through 4?
No. The stage 1 through 4 framework used in this site’s staging guides applies to diffuse malignant pleural mesothelioma. Peritoneal, pericardial, and tunica vaginalis mesotheliomas are not staged with the same system.
Should I see a specialist if mesothelioma is suspected?
A specialist evaluation can be especially useful when pathology is uncertain or treatment decisions are complex. A mesothelioma-experienced team can review imaging and pathology, decide whether additional testing is needed, and discuss treatment options in the context of the patient’s disease and health.
When to Seek Medical Advice
Persistent or unexplained shortness of breath, chest or abdominal pain, a new pleural or abdominal fluid collection, unexplained weight loss, or other ongoing symptoms should be medically assessed. None of these findings is specific to mesothelioma, and more common conditions are often responsible. A clinician can decide whether imaging, referral, or additional testing is appropriate.
References
- National Cancer Institute. What Is Mesothelioma? Updated May 16, 2025. View source.
- National Cancer Institute. Mesothelioma Causes and Risk Factors. Updated May 16, 2025. View source.
- National Cancer Institute. Mesothelioma Symptoms. Updated May 16, 2025. View source.
- National Cancer Institute. Mesothelioma Diagnosis & Prognosis. Updated May 16, 2025. View source.
- National Cancer Institute. Stages of Mesothelioma. Updated May 16, 2025. View source.
- National Cancer Institute. Treatment for Mesothelioma. Updated 2025. View source.
- National Cancer Institute. Malignant Mesothelioma Treatment (PDQ®) – Health Professional Version. Current 2026 version. View source.
- U.S. Food and Drug Administration. FDA approves pembrolizumab with chemotherapy for unresectable advanced or metastatic malignant pleural mesothelioma. September 17, 2024. View source.
- U.S. Food and Drug Administration. Nivolumab plus ipilimumab: first-line treatment of adult patients with unresectable malignant pleural mesothelioma. Marketing approval October 2, 2020. View source.
- Scherpereel A, Baas P, Nowak AK, et al. Five-Year Clinical Outcomes With Nivolumab Plus Ipilimumab Versus Chemotherapy as First-Line Treatment for Unresectable Pleural Mesothelioma in CheckMate 743. J Clin Oncol. 2026;44(9):742–749. PMID: 41734361. DOI: 10.1200/JCO-25-01328.
- Scherpereel A, Baas P, Nowak AK, et al. Erratum to the CheckMate 743 five-year update. J Clin Oncol. 2026;44(19):1852. PMID: 42228897. DOI: 10.1200/JCO-26-01289. The correction changed one Figure 2D table count from n=75 to n=76 and did not alter the headline efficacy results used in this article.
- National Cancer Institute. Asbestos Exposure and Cancer Risk Fact Sheet. Reviewed May 20, 2021. View source.
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