Distinguishing Mesothelioma

Differential Diagnosis
Differential diagnosis is specifically finding out the type of cancer a patient is afflicted with eliminating the possibility of others. In respect of mesothelioma also, since the symptoms are akin to adenocarcinoma, distinction has to be made by differential diagnosis.

Biopsy Procedure
During biopsy, tissue samples of mesothelioma patients are removed by the surgeon for testing in the laboratory. In the laboratory, the pathologist analyzes the slide bearing the tissue sample. The location in the body from where the sample is collected and information and history of the patient must be known to the pathologist. After the process of describing the sample tissue by gross examination, the sample is kept in a plastic cassette in a fixative for preservation. The tissue thus fixed is thereafter processed in a paraffin block from where the pathologist can cut off microscopic sections for staining and diagnosing the type of malignancy.

Mesothelioma Markers
It is the immunohistochemistry markers that can make distinction between adenocarcinoma and mesothelioma. By the method of immunohistochemistry, cell types are analyzed and identified. It is based on the principles of the antibodies binding to specific cell components. Earlier immunohistochemistry markers were negative due to their absence from specific type of cancer. Like mesothelioma could be diagnosed by absence of certain markers and not by their presence. A positive marker in adenocarcenoma diagnosis could be a negative marker in the diagnosis of mesothelioma. This made distinctive diagnosis difficult and sometimes inaccurate. It is only during recent years that positive markers expressed by mesothelioma can be used to distinguish this cancer from other types. Markers which are positive in mesothelioma are normally negative in adenocarcinoma. Some positive mesothelioma markers are calretinin, cytokeratin 5, mesothelin, etc. However even the markers cannot always specify the diagnosis and help of specialized laboratory may be required to conclusively diagnose mesothelioma patients.