Pathophysiology

Pathophysiology

The three main histological types of mesothelioma are sarcomatous, epithelial, and mixed. Pleural mesothelioma usually begins with discrete plaques and nodules that together to produce a sheet like the neoplasm. Tumor growth usually begins in the lower chest. The tumor can invade the diaphragm and the frame surface of the lung and interlobar fissures.

The tumor may also grow along drainage ways and thoracotomy. As the disease progresses, often extending into the lung parenchyma, chest wall and mediastinum. Pleural mesothelioma can spread to the esophagus, ribs, vertebrae, brachial plexus and the superior vena cava.



Asbestos, amphibole, crocidolite, amosite and, in particular, is the principal carcinogen implicated in the pathogenesis. Exposure to chrysotile asbestos is associated with a low incidence of mesothelioma. The asbestos-related industries are mining shipbuilding involving the use of asbestos, asbestos-cement manufacturing, ceramics, paper making, automotive parts (brake linings and asbestos), repair of railways, and isolation. In Turkey, the use of the substance fibrous erionite (similar to amphiboles) in construction has led to an epidemic of mesothelioma lung cancer. Environmental exposure to asbestos in areas contaminated by the substance may increase the incidence of mesothelioma.

Most malignant mesothelioma have a complex karyotype with extensive aneuploidy and transformation of many chromosomes. Loss of one copy of chromosome 22 is the most common abnormality.

Mesothelioma is a malignant pleural or peritoneal surfaces, this condition is usually associated with occupational exposure to asbestos. Wagner et al linked to asbestos mesothelioma classic 1960 study, 33 patients with mesothelioma who were exposed to asbestos in the mining area of ​​South Africa's Northern Province Western Cape. [1], 33 patients, 32 had been exposed to crocidolite, most of the type of asbestos cancer.


Asbestos mining and production peaked from the 1930s-1960s, and asbestos was used in a variety of products ranging from construction supplies to brake linings. During World War II, hundreds of thousands of civilian and military workers, through their occupations, were exposed to asbestos. Production slowed dramatically in the 1970s as the health risks of asbestos became known. Governmental restrictions were placed on its use, and alternative materials became available. Despite these changes, asbestos continues to be used in the manufacture of some fire safety products.


The clinical latency period between asbestos exposure and mesothelioma development is 35-40 years, and as a result, the number of mesothelioma patients has continued to rise despite decreased asbestos production. The most common findings on physical examination (79%) are signs of pleural effusion (eg, dullness to percussion, decreased breath sounds).

The diagnosis of mesothelioma should be done with care. A history of asbestos and radiological findings are consistent with mesothelioma justify inclusion in the differential diagnosis, but it is important that the diagnosis of mesothelioma can be done only with imaging studies. The most common diseases such as benign asbestos-related pleural metastasis of adenocarcinoma, may look identical to a radiographic mesothelioma. Biopsy with special stains and immunohistochemical and ultrastructural analysis are absolutely essential for the accurate diagnosis of mesothelioma.


Mesothelioma is very difficult to treat, treatment is usually surgical, although other treatments such as chemotherapy and radiation used. The two main surgical pleurectomy and extrapleural pneumonectomy (EPP).

Preferred examination

Chest radiography is the initial screening study, while computed tomography (CT) is preferable for the staging of the tumor.

Magnetic resonance imaging (MRI) to complete the CT in some patients. MRI provides a better definition of soft tissue (better soft tissue contrast) and allows the imaging of sagittal and coronal planes. [3]

PET can also be useful in delineating the extent of tumor or metastases [4].

Limitations of techniques

Chest radiography has a limited applicability. The radiological signs of mesothelioma are nonspecific and seen in other diseases, including metastatic carcinoma, lymphoma, asbestos disease and Benin. Small malignant pleural effusion is not visible on plain radiographs. Alternatively, large pleural effusion or pleural thickening dark mass, and therefore, since the disease is often underestimated in radiographs.

CT scans are more and better than plain radiography in relation to tumor characteristics and extent. Although MRI is superior to CT scanning in some areas, this advantage has not changed the surgical treatment in a study by Heelan et al. [5]

Neither CT and MRI provides an unequivocal diagnosis of mesothelioma, a biopsy is needed to diagnose the final fabric.