Asbestos exposure most commonly causes calcified plaques of the pleura (the lining of the chest cavity). Calcifications of the spleen, lung parenchyma, mediastinum, and hilum are often caused by chronic infection, but can be caused by cancer as well. Bullous changes of the lung are generally caused by emphysema, which is caused by smoking.
Sincerely,
Robert A. Wascher, MD, FACS
www.doctorwascher.com
Author, "A Cancer Prevention Guide for the Human Race"