Mesothelioma is a malignant tumor of the pleura (the membrane that lines the chest cavity and covers the lungs). There is an increased risk of mesothelioma in people exposed to asbestos dust.


Mesothelioma may cause no symptoms in some cases, whereas in others it may cause cough, chest pain, and breathing difficulty, especially if a pleural effusion (collection of fluid around the lung) develops.


A chest X-ray may show abnormal shadowing; the diagnosis can be confirmed by examination of a sample of fluid from an effusion or by pleural biopsy (removal of a sample of tissue for microscopic examination).


Surgical removal of a small tumor may result in a complete cure. Usually, however, the tumor is diagnosed only after it has spread over a large area of the pleura. In such cases, there is no effective treatment, although radiotherapy may help to alleviate symptoms.