Pleural fibrosis and calcification are usually benign chronic conditions that develop as a result of pleural inflammation or asbestos exposure. These disorders are suspected and diagnosed based on imaging studies.
Pleural fibrosis is a condition in which a person will develop fibrous tissue in the pleura (the casing in the chest cavity around the lungs and over the diaphragm or around the heart or around parts of the digestive tract). The fibrous tissues can develop in a small area of the pleura (localized) or be much more widespread.
Postinflammatory: Pleural inflammation commonly causes acute pleural thickening due to fibrosis. In most cases, the thickening resolves almost completely. Some patients are left with minor degrees of pleural thickening, which usually produces no symptoms or impairment of lung function. Occasionally, the lung becomes encased with a thick, fibrous pleural peel that limits expansion, pulls the mediastinum toward the side of disease, and impairs pulmonary function. Chest x-ray shows asymmetry of the lungs with thickened pleura (trapped lung). Differentiating localized pleural thickening from loculated pleural fluid may be difficult on x-ray, but this differentiation is easily made with CT scan.
Pleural fibrosis after inflammation can, on occasion, calcify. Calcification produces a dense image on the chest x-ray and almost always involves the visceral pleura. Postinflammatory calcifications are invariably unilateral.
Asbestos related: Exposure to asbestos can lead to focal, plaquelike pleural fibrosis, at times with calcification, occurring up to 20 yr after the initial exposure. Diagnosis is usually by chest-x-ray. The diameter of the plaques can vary from several millimeters to 10 cm. Any pleural or pericardial surface can be affected, but asbestos-related pleural plaques are usually in the lower 2/3 of the thorax and are bilateral. Calcification most often affects the parietal and diaphragmatic pleura and spares the costophrenic sulci and apices. Calcification may be the only evidence of exposure. Dense pleural fibrosis surrounding the entire lung and >1 cm in thickness can also follow asbestos exposure.