Epithelioid Mesothelioma

Epithelioid Mesothelioma

Epithelioid mesothelioma is generally a disease of older adults with more than 90% of cases being diagnosed after the age of 50. Epithelioid mesothelioma has one of the best prognosis, and most of the chemotherapeutic drugs work well against this type of cancer. Here we will see how.

Mesothelioma is divided into three categories according to cell types. These three types are epithelioid, sarcomatoid,Opens in a new tab. or biphasic.Opens in a new tab.

Cell type of mesothelioma is decided after examination of the cancer tissue under the microscopeOpens in a new tab., that is through histological examination. It is vital to find out the cell type, as the prognosis of mesotheliomaOpens in a new tab. is highly dependent on it. With that procedure is how we arrive to recognize epithelioid mesothelioma.

Among all the cell types epithelioid is the most common form that is found in about 60-70% of all the cases. Cells in epithelioid mesothelioma have a specific elongated patternOpens in a new tab. that is easily distinguishable under the microscope.

Differential Diagnosis Of Epithelioid Mesothelioma

Epithelioid Mesothelioma has to be differentiated from another common cancerOpens in a new tab. of the lungs called adenocarcinoma. The problem in differentiation arises due to the fact that both epithelioid mesothelioma and adenocarcinoma emerge from the so-called epithelium cells. Epithelium cells are very common in our body, lining all the mucus-producing body linings.

It is vital to differentiate between epithelioid mesothelioma and adenocarcinoma as they have entirely different treatment protocolsOpens in a new tab.. Fortunately, researchers have come up with lots of newer stains for making this differentiation activity easier, like immunochemistry, described below.

Immunochemistry For Accurate Differentiation And Recognition Of Epithelioid Mesothelioma

So here is where immunochemistry comes into the scenario to facilitate the diagnosisOpens in a new tab. of epithelioid mesothelioma.

Traditionally, electron microscopy and staining of hyaluronic acid have been used. However, nowadays immunochemistry markers are the more precise method of differential diagnosis. But things are not that simple as no single immunohistochemical marker may confirm the diagnosis of the particular type of cancerOpens in a new tab.. Mesothelin, calretinin, or cytokeratin 5/6 some of the commonly used immune markers.


Where Does Epithelioid Mesothelioma Occur?

More than 80% of cases of epithelioid mesothelioma are found in the lungs, the abdominal cavity is the next common location.

Pathogenesis Or Development Of Epithelioid Mesothelioma

Mesothelioma develops quite suddenlyOpens in a new tab. in most of the cases. One of the problems with it is difficulty in early diagnosisOpens in a new tab.. Radiological or imaging tools only work when the cancer has already advancedOpens in a new tab.. There are no blood tests or so-called serum biomarkers that could help in the early detection of cancerOpens in a new tab.. Epithelioid mesothelioma usually grows at locations from where it spreads very quickly. Thus there is a very short time in which it progresses.

Asbestos exposureOpens in a new tab. is the most significant culprit in the development of epithelioid mesothelioma. In practice, more than 80% of cases have some history of asbestos exposure in the United StatesOpens in a new tab., which paved the way for all kinds of legal actionsOpens in a new tab., individualOpens in a new tab. or collective actionsOpens in a new tab.. Thin fibers of asbestos are inhaled into the lungsOpens in a new tab., and they penetrate into the pleural space. Asbestos is known to cause inflammationOpens in a new tab., cell death, in pleural space.

Due to multiple exposuresOpens in a new tab., some of the pleural cells may mutate to cause cancer, though why this happens is not fully understood. But it is thoughtOpens in a new tab. that mesothelium cells are more susceptible to asbestosOpens in a new tab. as compared to other cells. But again there is an unexplained paradox since asbestos kills mesothelium cells quickly, how should cancer develop at all is not understood completely.

Staging and Prognosis

How long the person diagnosed with epithelioid mesothelioma would survive would depend significantly on the stage of the cancerOpens in a new tab.. The most commonly used staging method used is called the TNM method.

In TNM, T stands for the size of the tumor, N says about the amount of involvement of nearby lymph nodes. Whereas M stands for metastasis, it tells us about how far cancer has spreadOpens in a new tab. from the primary site.

It is common for us to hear that a patient has stages 1 to 4Opens in a new tab., which is in most cases accumulation or an average of the TNM system.

Staging is done with the help of physical examination, imaging, and histological examination. In some cases, the staging of the epithelioid mesotheliomaOpens in a new tab. condition may be corrected after the surgery.

Epithelioid mesothelioma is indeed a type of cancer with the best prognosisOpens in a new tab., with almost half of the patient can expect to survive after 3-years of diagnosisOpens in a new tab., in comparison around 5-7% would surviveOpens in a new tab. for three years in other subtypes of mesotheliomaOpens in a new tab.. If diagnosed early small number of cases can expect the long-term remissionOpens in a new tab. of the cancer.

Epithelioid Mesothelioma Diagnosis And Symptoms

Symptoms Of Epithelioid Mesothelioma

The symptoms of epithelioid mesotheliomaOpens in a new tab. would vary, depending greatly upon the location of the tumor.

Thus if the mesothelioma is present in the pleural cavityOpens in a new tab., where it can be also a case of pleural mesotheliomaOpens in a new tab., the symptomsOpens in a new tab. would be a cough, chest pain, hoarseness of voice, fever, fatigue, unintended weight loss, difficulty in breathing, and swelling of the face or upper limbs.

In the case of location in abdominal cavity symptomsOpens in a new tab. would be: pain in the abdominal region, in some cases there could be visible swelling in the abdomen, changes in the bowel movement like constipation, nausea, and vomiting.

Imaging is usually the first thing that any doctor would doOpens in a new tab. on suspicion of cancerOpens in a new tab. in general, and mesothelioma as a type of cancer. Ultrasound, MRI, CT scan, chest X-ray are some of the commonly used imaging methods. In most cases there would be multiple imaging, as after some kind of cancerous formation has been found, specialists would carry out additional, more specific imaging to confirm the diagnosisOpens in a new tab..

Biomarkers– looking for specific biomarkers in the blood is one of the tests that many cancerOpens in a new tab. specialists would use, mainly because of the ease of such tests. mesothelin-related peptides (SMRPs) are the most specific by-products of mesothelioma that can be detected in the blood. Though biomarkers may be easy to use, but they are not very accurate.

Biopsy– histological examination of the tumor or formation remains the golden standard for confirmation of the diagnosis. It is the most accurate test not only for verification of mesothelioma but also in differential diagnosisOpens in a new tab. and identifying the sub-types.

These three ways of identification of symptomsOpens in a new tab.: imaging, biomarkers, and the biopsy are also used for cancer in general and not just for epithelioid mesothelioma in particular.

Early Diagnosis: How Can Epithelioid Mesothelioma  Be Diagnosed Earlier?

Considering that it is a rare form of cancerOpens in a new tab., mass screening is not practicable. But regular testing can be done in those with proven long-term exposure to asbestosOpens in a new tab., especially in the age group above 50. Screening can be done with routine chest imaging and blood tests for mesotheliomaOpens in a new tab. specific markers.

Epithelioid Mesothelioma Treatment

We have two articles dedicated exclusively to mesothelioma treatments: This one and this one. in those articles, there are all the treatments explained in detail for all types of mesotheliomaOpens in a new tab..

In most cases of epithelioid mesothelioma, multimodal treatmentOpens in a new tab. would be the best option, which means a combination of surgery, radiotherapy, and chemotherapy. This applies to other types of mesothelioma as well, as we explained here thoroughlyOpens in a new tab..


Surgical treatment would depend on the location of cancerousOpens in a new tab. formation. In case of lungs it could involve partial removal of pleuraOpens in a new tab. or in more advanced cases even partial lung rejection along with more widespread removal of surrounding tissues.

The scope of the surgical operation would differ for each individual case. Similarly, in the case of abdomen cancerous tissue, it would be removed surgically. In the abdomen, HIPEC (Hyperthermic intraperitoneal chemotherapy) may also be used, which involves sterilization of the abdominal cavity by circulating the anti-cancer drugs at a higher temperature, which increases their effectiveness both due to higher concentration and temperature when compared to intravenous therapy.


Radiation therapy is something that would be used in most cases to shrink the tumor, either before or after the surgery. Radiation therapy is also used to decrease the pain related to cancerOpens in a new tab.. Radiation therapy is a non-invasive therapyOpens in a new tab. for the treatment of epithelioid mesothelioma.


Chemotherapy, which involves using the drugs to kill the cancer cells is the most commonly used treatmentOpens in a new tab.. It is generally used in any stage of the disease to either gain long-term remission or at least prolong the life. Chemotherapy drugs are known to be toxic and thus having a plethora of undesired side effects.

Read more about this treatment, in this articleOpens in a new tab..



Finally, there is a range of emerging therapies that promise to be effective and safer, like immunotherapy, and cell therapy.

See more about the epithelioid mesothelioma treatmentsOpens in a new tab. in these articlesOpens in a new tab..

Conclusions About Epithelioid Mesothelioma And Further Reading

Mesothelioma is among the rare type of cancersOpens in a new tab., that is responsible for less than 1% of new cancer cases each year. It is a type of cancer that has shown a strong relation to the asbestos exposureOpens in a new tab. and thus is found most commonly in lungsOpens in a new tab.. Apart from asbestos exposureOpens in a new tab., common in some factoriesOpens in a new tab., certain types of viral infections are considered to be among the reasons of this cancer.

Mesothelioma is generally divided on the basis of its location and cell types. Mesothelioma is the cancer of outer serous layer of internal organs like heart, lungs, intestines, and testicles. As per site, lungs are affected most commonly with 80% of all cases of mesotheliomaOpens in a new tab., followed by abdomen. Epithelioid mesothelioma is one of the most common types of condition.

Mesothelioma is an aggressive kind of cancerOpens in a new tab., that is usually difficult to diagnose in early stagesOpens in a new tab. and hence is characterized by poor prognosisOpens in a new tab., with most patients not surviving two yearsOpens in a new tab. after the diagnosisOpens in a new tab..


  1. AJCC – What is Cancer Staging? https://cancerstaging.org/references-tools/Pages/What-is-Cancer-Staging.aspx in relation to epithelioid mesothelioma. Accessed April 2, 2020.
  2. Can Malignant Mesothelioma Be Found Early? https://www.cancer.org/cancer/malignant-mesothelioma/detection-diagnosis-staging/found-early.htmlOpens in a new tab.. Accessed April 2, 2020 for the topic related to epithelioid mesothelioma
  3. Robinson BW, Musk AW, Lake RA. Malignant mesothelioma. The Lancet. 2005;366(9483):397-408. DOI:10.1016/S0140-6736(05)67025-0.
  4. Sekido Y. Molecular pathogenesis of malignant mesothelioma. Carcinogenesis. 2013;34(7):1413-1419. DOI:10.1093/carcin/bgt166.
  5. Inai K. Pathology of epithelioid mesothelioma. Environ Health Prev Med. 2008;13(2):60-64. DOI:10.1007/s12199-007-0017-6.
  6. Ordóñez NG. The Immunohistochemical Diagnosis of Mesothelioma: A Comparative Study of Epithelioid MesotheliomaOpens in a new tab. and Lung Adenocarcinoma. The American Journal of Surgical Pathology. 2003;27(8):1031.

Sandra Eades

Hello I am Sandra Eades, physician, researcher and author from Australia. I am working currently as researcher for a private institution. I have studied in Britain and Australia, where I currently reside. I write about research topics in the organization of the public health government agencies. For the iMS I write about general medical conditions. I also research scholar sources to provide information to writers of other articles. I also check the citations of scholar papers. Finally, I read other articles before they are published. I am also a mother of three children!

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