Malignant pleural effusion is caused by cancer cells growing in the pleural cavity, causing damage and leading to effusion. Malignant pleural effusion is a treatable disease, however, the disease often progresses to a more severe stage, threatening the patient's life.

When there is more fluid than normal in the pleural cavity, it is called a pleural effusion. Pleural effusion can occur in both adults and children.

The main cause of pleural thickening is pleural effusion. Therefore, when it is identified and treated completely, it also means that the pleural effusion stops.

To detect lung lesions, in addition to chest X-ray and CT scan, patients are also prescribed pleural fluid aspiration and biopsy to obtain more diagnostic information.