Epithelioid mesothelioma is the most common form of mesothelioma and accounts for 50 to 70 percent of mesothelioma cancer cells. The individual cells are relatively uniform in shape with a unique tubular pattern and a cell nucleus that, when viewed under high magnification, is visibly distinguishable from other cell nuclei. However, other types of cancer can take a similar form, and if these cancers appear in the mesothelium, they can be confused with epithelioid mesothelioma. Adenocarcinoma is a type of cancer often confused with epithelioid mesothelioma.
Epithelioid Mesothelioma Versus Adenocarcinoma
Mesothelioma, including epithelioid mesothelioma, is a type of cancer that occurs in the mesothelium, which is an epithelium (protective layer of tissue) that surrounds certain organs. Epithelia, which are found throughout the body, exist to separate different bodily environments. For example, epithelial cells are found in the skin, which separates the outside of the body from the inside of the body. Depending on the location, an epithelium can serve many functions, including protection, absorption, filtration, excretion, secretion or sensory reception.
Adenocarcinoma is another type of cancer that can be found in the mesothelium. However, unlike epithelioid mesothelioma, adenocarcinoma does not originate in the mesothelium, but rather in the lining or inner epithelium of an organ. When an adenocarcinoma occurs in the lining of the lungs it can spread to the mesothelium, or pleura, surrounding the lungs. Since epithelioid mesothelioma can also appear in the pleura, it can be easily confused with adenocarcinoma.
Furthermore, since both epithelioid mesothelioma and adenocarcinoma derive from epithelial tissue, they have a similar cellular appearance. Although research does show that the tumor cells in epithelioid mesothelioma are usually more regularly uniform, cube-shaped and spread out than the tumor cells in adenocarcinoma (which are more columnar and crowded), this distinction is difficult to make on a case-by-case basis. To add to this confusion, chemical staining of epithelioid mesothelioma and adenocarcinoma cancer cells sometimes shows similar results.
The clinical signs for adenocarcinoma of the lung and malignant mesothelioma are also similar. The symptoms of these diseases, both of which typically affect the older population, include chest pain, pleural effusions (fluid build-up) and respiratory difficulty. This is why cancer of the mesothelium, or epithelioid mesothelioma, and cancer of the lung epithelium, adenocarcinoma, are often mistaken for one another and therefore misdiagnosed.
If you or a loved one has had asbestos exposure and received a diagnosis of adenocarcinoma, it may be worthwhile to seek a second diagnostic evaluation, either by the same physician or an oncology specialist who has experience in mesothelioma cases. The mesothelioma prognosis for patients with epithelioid mesothelioma is typically quite bleak.