Mesothelioma is a rare neoplasm that arises from mesothelial cells lining the parietal and visceral pleura and can present in a localized or diffuse manner. The localized variant (solitary fibrous tumor) is very uncommon and usually presents as a well-defined, encapsulated tumor that is not associated with exposure to asbestos. Typically, the lesions are diagnosed as an asymptomatic mass on a chest radiograph. Complete surgical resection is the treatment of choice.

The diffuse variant presents as a locally aggressive tumor commonly associated with asbestos exposure (75%).A long latency period between asbestos exposure and the development of the disease has been reported.Although smoking alone is not a reported risk factor, other factors such as radiation therapy and various occupational exposures have been implicated.In the late 1990s an association between simian virus 40 (SV 40) and mesothelioma was investigated.

The clinical presentation of a patient with diffuse malignant pleural mesothelioma (MPM) is variable; therefore, a thorough clinical evaluation is essential. Dyspnea secondary to pleural effusion or encasement of the lung and chest pain from tumor infiltration into the chest wall and

Depending on the extent of disease, the chest radiographic findings may be quite variable. Typically, chest radiography demonstrates pleural thickening with or without pleural effusion. Chest CT and MRI are particularly effective in determining the presence of advanced disease, such as transdiaphragmatic involvement or mediastinal organ invasion.Echocardiography also is helpful in ruling out pericardial invasion. In the future, positron emission tomography (PET) also may prove to be a useful tool in determining the extent of tumor invasion.

A number of techniques are used to confirm the diagnosis of MPM, including thoracocentesis of pleural effusion and pleural biopsy (open, VATS, and closed).Open or VATS biopsy provides the best method to obtain a tumor sample sufficient to distinguish mesothelioma from other tumors such as adenocarcinoma and to determine the specific subtype of MPM. Frequently, immunohistochemistry techniques and electron microscopy performed by an experienced pathologist are required to confirm the diagnosis of MPM.

Microscopically, malignant mesothelioma originates from mesothelial cells that line the pleural cavity. Three histologic subtypes of mesothelioma have been identified; these are epithelial, sarcomatous, and mixed histologies.The histologic subtype has been shown to affect survival dramatically, with epithelial histology having a more favorable prognosis than the other two subtypes. MORE>