Mesothelioma Symptoms by Type: Pleural and Peritoneal

This page is for anyone worried about signs of mesothelioma, especially people with a history of asbestos exposure, and their families.

Mesothelium is the thin tissue that lines the lungs, the abdomen, the heart, and other organs. Mesothelioma is cancer of that lining. It can start in the chest, the abdomen, or elsewhere.

That location decides the symptoms. Cancer in the chest lining presses on breathing. Cancer in the abdominal lining presses on the gut. The rest of this page follows that split.

NCI's symptom page is short and specific. It names shortness of breath and pain under the rib cage first. It then adds that the cancer sometimes makes fluid collect in the chest or the abdomen.

The full list of signs to check with a doctor:

• Trouble breathing.
• Cough.
• Pain under the rib cage.
• Pain or swelling in the abdomen.
• Lumps in the abdomen.
• Constipation.
• Problems with blood clots, meaning clots that form when they should not.
• Weight loss with no known cause.
• Fatigue, or feeling very tired.

NCI is careful to add that any of these can come from the fluid, from the cancer, or from something else entirely.

Pleural mesothelioma grows in the pleura. That is the double layer of tissue wrapping each lung and lining the chest wall.

Trouble breathing usually comes first. Often the tumor itself is not the cause. Fluid is. A pleural effusion is a pool of fluid between the two layers of the pleura, and it squeezes the lung from outside. NCI's summary for doctors says that effusions, in the chest or the abdomen, are a major symptom problem for at least 66% of patients.

Cough and pain under the rib cage follow.

Peritoneal mesothelioma grows in the peritoneum, the lining of the belly. Its symptoms can seem like a digestive problem:

• Pain in the abdomen
• Swelling
• Lumps that can be felt
• Constipation

Fluid can gather here too, which is what produces the swelling and the feeling of tight fullness. Weight loss and fatigue can come with disease at either site.

Blood clots are on NCI's list, and they are easy to miss as a cancer sign. A clot in a leg vein or a lung can be the first thing that sends someone for scans. Call 911 for sudden trouble breathing or chest pain. Our overview of mesothelioma covers the disease more broadly.

This is the part that confuses many people. Latency is the time between exposure to asbestos and the first signs of disease. NCI says it usually takes a long time for mesothelioma to form after asbestos exposure. Its asbestos fact sheet says it can take 10 to 40 years or more for symptoms of an asbestos-related condition to appear.

That is a long time. A shipyard job, an insulation trade, a school building, or a home repair stops feeling tied to a new cough. Yet NCI's clinical summary reports a history of asbestos exposure in about 70% to 80% of cases. So the history is worth raising with your doctor, even when it feels like long ago. Our page on asbestos and cancer covers which trades carried the heaviest exposure.

NCI's asbestos fact sheet lists a wider set of symptoms for anyone with an exposure history. It advises checking with a doctor for:

• Shortness of breath, wheezing, or hoarseness.
• A cough that keeps getting worse.
• Coughing up blood. Get care right away if this happens.
• Chest discomfort.
• Difficulty swallowing.
• Weight loss with no known cause.
• Fatigue.

Those symptoms do not point only at mesothelioma. They also fit asbestosis, pleural thickening, pleural plaques, and lung cancer.

Symptoms are vague. The tissue itself is also hard to read. NCI's clinical summary says attempts to diagnose by cytology (looking at cells in fluid) or needle biopsy of the pleura often fail. Telling mesothelioma from adenocarcinoma in a small sample can be very hard. Thoracoscopy uses a camera inside the chest to take bigger samples. NCI calls it valuable for getting enough tissue.

Pathologists, the doctors who examine tissue, rely on specific stains. Pancytokeratin stains are positive in nearly all mesotheliomas. Four more stains help identify the epithelioid type: cytokeratin 5 and 6, calretinin, WT-1, and D2-40. That type is roughly 60% of diagnoses. Chest x-ray is still the most common first test for asbestos disease. NCI notes it shows lung damage, not the fibers themselves.

• Chest symptoms affect breathing.
• Abdominal symptoms affect the gut.
• Your exposure history is worth telling your doctor early.

• National Cancer Institute, Mesothelioma Symptoms, updated May 16, 2025, accessed October 2, 2026
• National Cancer Institute, Malignant Mesothelioma Treatment (PDQ) - Health Professional Version, updated May 12, 2025, accessed October 2, 2026
• National Cancer Institute, Asbestos Exposure and Cancer Risk, accessed October 2, 2026