Epithelioid Mesothelioma

Epithelioid mesothelioma is the most common mesothelioma cell type, accounting for more than half of cases. It is also the most treatable cell type.

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Written by Jenna Campagna, RN

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Important Facts About Epithelioid Mesothelioma

  • Epithelioid mesothelioma is a frequent cell type for this cancer. It’s diagnosed in 70% of cases.
  • All treatment options are available for epithelioid mesothelioma.
  • Patients with this cell type have promising survival rates following surgery.

What Is Epithelioid Mesothelioma?

epithelioid cell

Epithelioid Cell Type

Epithelioid mesothelioma is the result of healthy epithelial cells mutating into cancerous cells. Epithelial cells can be irritated and genetically altered by asbestos.

Upon entering the body, asbestos fibers can lodge into cells along the mesothelium, which lines the lungs, abdomen and heart. The mesothelium is made up of epithelial cells.

Patients with epithelioid mesothelioma often have a better prognosis and more treatment options than people with sarcomatoid or biphasic mesothelioma.

Characteristics of Epithelioid Mesothelioma Cells

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Cell Prevalence

Epithelioid mesothelioma accounts for between 50% and 70% of mesothelioma cases.

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Cell Description

Epithelioid cells have a clearly defined, elongated egg-shape. They often clump together and have a pink cytoplasm. The cells’ visible nuclei make them easily distinguishable.

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Cell Behavior

Epithelioid cells divide faster than other mesothelioma cells, contributing to faster tumor growth. However, the cells stick to each other, which slows metastasis and makes them easier to remove during surgery.

Epithelioid Mesothelioma Symptoms

Epithelioid cells closely resemble cell types that make up adenocarcinoma, which is a type of cancer that forms inside organs like the lungs, colon and breast.

Symptoms of epithelioid pleural mesothelioma include:

  • Shortness of breath
  • Chest or lower back pain
  • Coughing
  • Difficulty swallowing
  • Arm or face swelling
  • Pleural effusions

Symptoms of epithelioid peritoneal mesothelioma include:

  • Abdominal pain
  • Ascites (fluid in the abdomen)
  • Nausea and vomiting
  • Constipation
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Diagnosis

In order to diagnose a patient for epithelioid mesothelioma, a physician will take a biopsy. By studying the pathology report, doctors will check for the presence of malignant mesothelioma cells.

A pathologist will use a process called immunohistochemistry to confirm the patient’s mesothelioma diagnosis. Immunohistochemistry is a process to identify antigens in cells.

The immunohistochemical markers for epithelioid mesothelioma

Calretinin

Demonstrated in nearly all epithelioid mesothelioma cases

Cytokeratin 5 or 5/6

Expressed in between 75% and 100% of cases

Wilms’ tumor-I antigen (WT1)

Demonstrated in between 90% and 100% of cases

Podoplanin (D2-40)

Demonstrated in between 90% and 100% of cases

Treatment

Epithelioid mesothelioma often has more treatment options than the other mesothelioma cell types. The primary treatment options for this epithelioid mesothelioma are surgery, chemotherapy and radiation.

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Surgery

Some epithelioid mesothelioma patients may be eligible for an extrapleural pneumonectomy (EPP), a surgery which can significantly increase life expectancy.

A study published in the Annals of Thoracic Surgery showed the effectiveness of extrapleural pneumonectomy for epithelioid mesothelioma patients. The average survival time was 20.6 months.

Some patients can undergo pleurectomy with decortication (P/D) surgery. This operation spares the nearby lung.

Those with epithelioid peritoneal mesothelioma can undergo cytoreductive surgery. This procedure has increased survival times to around five years.

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Chemotherapy, Radiation and Emerging Methods

Mesothelioma specialists use other treatments for this type of mesothelioma. Chemotherapy and radiation are the two standard forms.

Pemetrexed and cisplatin are the two chemotherapy drugs approved by the United States Food and Drug Administration for mesothelioma. Radiation is often used as a second-line treatment.

The Orphanet Journal of Rare Diseases published a report that radiation therapy combined with EPP increases epithelioid patients’ median survival to 33 months (nearly three years).

There have also been successes with alternative treatment options, such as gene therapy, immunotherapy, photodynamic therapy and intensity-modulated radiation therapy. The FDA approved two immunotherapy drugs (Opdivo and Yervoy) for unresectable pleural mesothelioma cases. They proved effective for epithelioid cases.

Subtypes of Epithelioid Mesothelioma

Subtypes of this mesothelioma cell type have different sizes, shapes and structures. They all contain epithelioid cells; however, these subtypes may react differently to treatment. The majority of these subtypes are rare and often benign.

  • Adenoid
  • Small cell
  • Cystic
  • Papillary
  • Deciduoid

Prognosis

Cell type is one of the most important factors affecting a patient’s mesothelioma prognosis. According to the Orphanet Journal of Rare Diseases, most patients who survive for two years after their diagnosis have epithelioid mesothelioma.

If you have epithelioid mesothelioma, then your prognosis varies. The difference is largely whether you have the pleural mesothelioma or peritoneal mesothelioma:

  • According to a study published on UpToDale, epithelioid pleural mesothelioma patients survive for an average of 19 months.
  • Epithelioid peritoneal mesothelioma patients survived for an average of 55 months.

Other factors, like age, disease stage and overall health, can impact any patient’s life expectancy.

There are many ways patients with epithelioid mesothelioma can improve their survival. One way is seeing a specialist or opting for new treatments. Learn how mesothelioma survivors extended their lives in our free Mesothelioma Survivors Guide.

Common Questions About Epithelioid Mesothelioma

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What does epithelioid mesothelioma look like?

Epithelioid mesothelioma cells have a clear egg shape. They have a visible pink cytoplasm (the cell area surrounding the nucleus) and clump together with defined borders. Epithelioid cells also have visible, dark-colored nuclei.

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How common is epithelioid mesothelioma?

Epithelioid mesothelioma occurs in at least 50% of all cases of this cancer. There are around 3,000 diagnosed mesothelioma cases in the United States each year, which means there are at least 1,500 epithelioid cases. This cell type can occur in both pleural mesothelioma and peritoneal mesothelioma.

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What is the survival time for epithelioid mesothelioma?

This mesothelioma cell type has the best prognosis of the three cell variations. Pleural mesothelioma patients live for an average of 19 months after diagnosis. Peritoneal mesothelioma patients survive for an average of 55 months.

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How is epithelioid mesothelioma treated?

All treatment options are possible for epithelioid mesothelioma. The cells stick together, which helps doctors remove large chunks of cells and tumors during surgery. Chemotherapy, radiation, immunotherapy, tumor treating fields and other options are all used to treat epithelioid mesothelioma.

Last Edited: February 26, 2021.

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