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Epithelioid Mesothelioma

What is Epithelioid Mesothelioma?

Epithelioid mesothelioma is the most common histological type of this rare form of asbestos cancer. Though the vast majority of mesothelioma patients are diagnosed with this type of the disease, it responds the best to various treatments when compared to either sarcomatoid or biphasic mesothelioma. This better treatment response leads to epithelioid mesothelioma patients having better prognoses than patients diagnosed with other types.

Though both pleural and peritoneal mesotheliomas can express an epithelioid histological type, epithelioid cells are most common in malignant pleural mesotheliomas (MPM).

Epithelial Cells and Mesothelioma

Epithelioid mesothelioma gets its name from the shape of the cancer cells as seen under a microscope.

Epithelial cells make up the majority of tissues that line the interior body organs as well as cover flat surfaces. Human skin is comprised of epithelial cells, as is the lining of body cavities such as the stomach, heart, and lungs.

These cells typically appear as elongated rectangles or pointed ovoid shapes. They also have a very well defined and visible nucleus. Epithelioid mesothelioma cells share this same basic construction and look very similar under magnification. They are also present in patients diagnosed with biphasic mesothelioma, which is a combination of epithelioid and sarcomatoid cell types.

Rates of Epithelioid Mesothelioma

Epithelioid cells are common in both malignant pleural and peritoneal mesothelioma. Epithelioid mesotheliomas can account for up to 70% of all cases of this rare form of cancer.

The histological profile of patients diagnosed with epithelioid mesothelioma breaks down as follows:

  • 81% are men
  • 95% are caucasian
  • age of diagnosis is usually after age 45, with the average age of diagnosis being around 50

Diagnosis of Epithelioid Mesothelioma

Though several new diagnostic tests are currently in the experimental stage, biopsy remains the only way to accurately diagnose epithelioid mesothelioma.  Depending on the type, number, and location of the mesothelioma tumors, biopsies may be acquired through endoscopic procedures such as thorascopic surgery or they may require more extended surgical procedures including tumor removal.

Regardless of how the biopsy is acquired, histological staining is the next step. Laboratory technicians add certain chemicals to the tissue sample which stain the cells so they are visible to the human eye. The tissue samples are then examined under a microscope. Determination of epithelioid mesothelioma is made by comparing the cell structure of the tissue sample with existing examples of the disease.  Diagnosis can be tricky though. Epithelioid mesothelioma can closely resemble other cancers – especially adenocarcinoma.

New research suggests that many patients diagnosed with epithelioid mesothelioma may actually be suffering from undiagnosed biphasic mesothelioma. One recent study published in Journal of Thoracic Oncology examined extended histological testing in patients who had undergone surgical procedures to remove mesothelioma tumors. These extended post-surgical tests determined that within the study’s population 62 patients had been erroneously diagnosed as suffering from epithelioid mesothelioma when their cancer was actually of the biphasic type.

While this discrepancy did not have a measureable effect on the type of treatments oncologist would have chosen, it would have had a marked effect on the predicted prognosis for these misdiagnosed patients.

Treatment of Epithelioid Mesothelioma

Standard treatments of epithelioid mesothelioma are often the same as for other types of mesothelioma. Traditional treatments include:

  • Surgery
  • Chemotherapy
  • Radiation therapy

Alternative mesothelioma treatments, such as gene therapy, immunological therapy, and variations on chemotherapy and radiotherapy (i.e. photodynamic chemotherapy) have gained some acceptance in recent years.

Prognosis of Epithelioid Mesothelioma

Epithelioid cell types respond more readily to traditional forms of cancer treatments used to combat mesothelioma including chemotherapy and radiation. This means that patients diagnosed with epithelioid mesothelioma tend to have better prognosis.  On average, only 40% of mesothelioma patients survive for longer than one year. However, a study completed in 1996 discovered that 60% of epithelioid mesothelioma patients survived at least that long. Less than 25% of the non-epithelioid mesothelioma patients within that same study had as long survival times.

However, experts are quick to note that individual survival rates depend much more on the location, size, and type of tumor rather than on the histological type associated with the disease.

For more information and to find out what your rights to file a mesothelioma lawsuit to cover costs of mesothelioma treatment and ensure financial security for yourself and your family, call 1-800-440-4262 today to speak with one of our asbestos attorneys.