Mesothelioma is a rare form of cancer in which malignant cells are found in the sac lining the chest (the pleura) or abdomen (the peritoneum). Most people with malignant mesothelioma have worked on jobs where they breathed asbestos, a fiber that was used in insulation materials.

Symptoms include shortness of breath, chest pain, or pain or swelling in the abdomen.

Treatment, which includes surgery, chemotherapy, and radiation, is based on whether the cancer has spread (metastasized) and the stage of the cancer.