Localized thickening of the pleura is usually not cancerous. Pleural thickening is more common and is generally a phenomenon of increased thickness of the pleura due to fibrosis caused by fibrin deposition and granulation tissue proliferation on top of pleural lesions. It is often the result of healing from previous exudative pleurisy and pleural effusion. Pleural thickening can be classified as limited or extensive. Extensive thickening of the dirty pleura can affect the respiratory function of the lungs, while extensive thickening of the wall pleura can narrow the rib cage. Common causes are usually pneumothorax, hemothorax, trauma, mesothelioma, tuberculous pleurisy and septic pleurisy. Pleural thickening, in most cases, does not require special treatment. The symptoms of mild chest tightness will be gradually compensated and reduced or disappeared, and the exercise can be strengthened by doing chest expansion and deep breathing regularly.