A thoracic disease which may involve inflammation of pleura, collection of air within the pleural cavity, abnormal collection of pleural fluid, abnormal growths on the pleura (pleural tumor) and pleural plaques. The main causes of pleural diseases including pleural effusions are congestive heart failure, malignancy, parapneumonic infections and pulmonary embolism. [ http://purl.obolibrary.org/obo/ECO_0007638 ]