Sarcomatoid Mesothelioma Cancer
Continued from: Mesothelioma Cancer Cells
Sarcomatoid mesothelioma accounts for only about 10 to 15 percent of the mesothelioma cancer cells and it is the least common form of mesothelioma. Sarcomatoid cells are typically oval shaped, but more irregular. The nucleus of sarcomatoid cells is not as clearly visible under an electron microscope as the nuclei of epithelioid mesothelioma cancer cells. Because the irregular oval shape is a common among cancer cells, sarcomatoid mesothelioma can be confused with sarcomatoid carcinoma and with sarcoma.
Sarcomatoid Mesothelioma Versus Sarcomatoid Carcinoma
Sarcomatoid mesothelioma is often confused with a wide variety of other types of cancer because of the sarcomatoid appearance, including sarcomatoid carcinoma. Although sarcomatoid cancer appears in other parts of the body, such as the kidney, it is relatively rare in the lungs. No more than 1.3 percent of lung carcinomas are of the sarcomatoid type.
Pulmonary sarcomatoid carcinoma is the type most often confused with sarcomatoid mesothelioma. Similar to sarcomatoid mesothelioma, sarcomatoid carcinomas of the lung are much more common in men (four times more likely than in women) and there is a strong association with smoking. Pulmonary sarcomatoid carcinoma and sarcomatoid mesothelioma also share certain symptoms, such as chest pain, pleural effusions and respiratory difficulty.
Sarcomatoid Mesothelioma Versus Sarcoma
Sarcomatoid mesothelioma also can be confused with high-grade sarcoma. While carcinoma affects the epithelium, sarcoma arises in the supportive tissue (bone, cartilage, fat or muscle). If the sarcoma spreads to the pleural surface, it can be difficult to differentiate from sarcomatoid mesothelioma.
Sarcoma cells and sarcomatoid mesothelioma cells can have a similar appearance under an electron microscope, and the staining of the tumor cells can provide similar results. In these cases, the pathologist must be careful to compare the appearance and staining of the cells, along with the overall appearance (localized versus diffuse pleural-based mass) and regularity of the tumor, when making a definitive diagnosis of malignant mesothelioma.
If you or a loved one has been diagnosed with high-grade sarcoma of the lungs or pulmonary sarcomatoid carcinoma and you have had previous asbestos exposure, it may be best to seek a second thorough examination from your current physician or from an oncologist who specializes in mesothelioma. The mesothelioma prognosis of patients with sarcomatoid mesothelioma is usually grim.
[Page updated March 2008]