Malignant mesothelioma is a diffuse tumor that affects men more frequently than women.
The latent period between exposure to asbestos and onset of symptoms can be 20 to 40 years. The median age of onset of symptoms is 70. Progressive pain and shortness of breath occurs. The tumor is usually associated with a pleural effusion . Differentiation of the tumor from other conditions of the pleura can be difficult even with tissue from an open lung biopsy .