Mesothelioma Questions

The most common cell type is epitheliod. This type is seen in fifty to seventy percent of patients. The epitheliod cell shape and appearance with staining under a microscope is similar to adenocarcinoma and they are often confused. Diagnosis is made by cell characteristics which include uniformity in size, cube shape, and a very visible nucleus within the cell. Life expectancy for patients with epitheliod mesothelioma is 8.5 months. Sarcomatoid mesothelioma is the least common type appearing in ten to fifteen percent of patients. Cell shape is oval and more irregular than epitheliod cells. The nucleus of the cell is also less visible than that of the epitheliod cell. The life expectancy with sarcomatoid cell type is seven months. Thirdly is biphasic mesothelioma which contains both epitheliod and sarcomatoid type cells. There are sharply defined areas of each cell type within a biphasic tumor. The life expectancy for this type of tumor is six months.

Malignant mesothelioma is classified into the histologic subtypes of epithelial, sarcomatoid, and mixed variants. Grossly, the tumors arise as firm, gray plaques and nodules that coalesce into a sheet like structure.  Pleural mesothelioma typically arises in the lower chest, and early invasion into the diaphragm, chest wall, interlobar fissures and mediastinum are common.  Hematologic spread can cause metastasis to the liver, lung, bone, and adrenal glands.  Almost 80 percent of pleural mesothelioma cases are associated with documented exposure to asbestos, the commercial name for a group of  silicate minerals that are used in cement, insulation, tiles, brake linings, and shipbuilding.  Though the federal government has attempted to restrict exposure to these minerals since the 1970s, both occupational and non-occupational exposure to small amounts of asbestos can contribute to mesothelioma.  Asbestos workers have almost a 50 percent chance of dying from a malignancy, primarily lung carcinoma or mesothelioma.