MESOTHELIOMA - A mesothelioma is a tumor of the lining of the lung and chest cavity, known as the pleura. Benign mesotheliomas do occur but are much more rare than the malignant type. Malignant mesothelioma affects men more commonly, and about 80% of cases have a history for prior exposure to asbestos. Symptoms include chest pain, shortness of breath, cough, and weight loss.