I. Symptoms: 1. The limited type may have no obvious discomfort or only chest pain and shortness of breath after activity. 2, Diffuse type has more intense chest pain, shortness of breath, and wasting. 3. The affected side of the thorax is limited in activity, full, with turbid percussion and reduced or absent breath sounds. 4. There may be enlarged supraclavicular fossa and axillary lymph nodes. Diagnosis: 1, chest pain, shortness of breath, wasting and other symptoms. 2.Signs of pleural effusion and pleural thickening. 3.Pleural nodular shadow is seen on chest film or chest CT. 4, nodules can be seen on thoracoscopy, and the active tissue can be clamped for clear etiological diagnosis. Clinical features: Pleural mesothelioma is a primary tumor of the pleura, and there are limited type (mostly benign) and diffuse type (both malignant). Among them, diffuse malignant mesothelioma is one of the tumors with the worst prognosis in the chest. Most patients are between the ages of 40-70 years, with more men than women. The most common first symptoms are chest pain, cough and shortness of breath. Fever, sweating or arthralgia may also be the main complaints. About half of the patients have massive pleural effusion with severe shortness of breath. Chest pain is often more severe in those without massive pleural fluid, and weight loss is common. In advanced cases, there may be enlarged cardiac shadow and soft tissue shadow and rib destruction caused by pericardial leakage. For patients with suspected malignant pleural mesothelioma, CT examination is most useful. Cytologic examination of the pleural fluid is also useful for diagnosis. In routine laboratory tests, some patients may have thrombocytosis and elevated serum carcinoembryonic antigen (CEA). For those who cannot be diagnosed clearly by routine examination, pleural biopsy can be performed by thoracoscopy. Generally, most patients can get the diagnosis as a result. 1.Benign pleural mesothelioma is mostly limited in growth, so it is also called benign limited pleural mesothelioma. (1) The tumor is often a round mass with envelope, and the base may be small, with a tip attached to the pleura, or wide base attached to the pleura. Some tumors may be lobulated and firm. Most of the tumors are small, with an average diameter of 1~3 cm, but there are also cases with a diameter of 12 cm or more. (2) Microscopic tumor tissue is mostly composed of spindle-shaped fibroblast-like tumor cells, which are arranged like fibroids. Some tumors have papillary, adenoid or solid structures formed by epithelial tumor cells within the fibroblast-like cells, which is called bidirectional mesothelioma. This tumor is slow growing and easy to remove surgically. After removal, recurrence is rare and the clinical prognosis is good. Malignant pleural mesothelioma: It is a highly malignant tumor with diffuse infiltration and expansion along the pleural surface, so it is also called malignant diffuse pleural mesothelioma. This tumor is mostly seen in the elderly, and its development has been proved to be closely related to the inhalation of asbestos dust. Typical cases present with shortness of breath, chest pain and pleural effusion, and the pleural fluid is often bloody. (1) The characteristic manifestation of neoplasm is diffuse thickening of pleura in the form of multiple nodules, which are ill-defined, grayish-white and vary in size, and isolated nodular masses are quite rare. The tumor often involves most of the pleura on one side, but may also spread to the contralateral pleura, interlobular lung, pericardium, chest wall, diaphragm and even lung tissue, and in a few cases may extend to the peritoneum. (2) The microscopic histological conformation is complex. According to the different cellular components of the tumor, those with tubular and papillary structures are called adenoid papillary type; those composed of spindle-shaped cells and collagen fibers are called sarcomatoid type; those with a mixture of the above two components are called mixed type (or bidirectional type). The mixed type and adenoid papillary type account for more than 70% of the total number of tumors, and the mixed type is the most common. All types of tumor cells have different degrees of heterogeneity and varying degrees of nuclear division. Malignant pleural mesothelioma has a poor prognosis, but if most of the tumors can be surgically removed and treated with radiotherapy and chemotherapy, patients can survive for more than two years.