Epithelioid Mesothelioma

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

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Written by Jenna Campagna, RN

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What Is Epithelioid Mesothelioma?

epithelioid cell

Epithelioid Cell Type

This form of mesothelioma is the result of healthy epithelial cells in your body mutating into cancerous cells. Epithelial cells are prevalent in the human body but can be irritated by asbestos.

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

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

Characteristics of Epithelioid Mesothelioma Cells

cell prevalence

Cell Prevalence

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

cell description

Cell Description

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

cell behavior

Cell Behavior

Epithelioid cells divide faster than other mesothelioma cell types, contributing to faster tumor growth. However, the cells stick to each other, which slows down 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, the doctor will check for the presence of malignant mesothelioma cells. If cancerous cells are in the biopsy, a physician may ask the patient about their history of asbestos exposure.

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 cellular types of the cancer. The primary treatment options for this mesothelioma cell type are surgery, chemotherapy and radiation.

surgery

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 for these patients was 20.6 months.

If the mesothelioma tumors haven’t spread from the pleura to the actual lung, then patients can undergo the lung-sparing pleurectomy with decortication (P/D) surgery.

Those with epithelioid peritoneal mesothelioma could undergo cytoreductive surgery. This procedure has increased survival times of patients to around five years following diagnosis.

chemotherapy

Chemotherapy, Radiation and Emerging Methods

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

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 an article that states radiation therapy combined with EPP increases epithelioid mesothelioma patients’ median survival times 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. These types of treatment methods, while not yet FDA approved, are currently being researched in hopes of developing a mesothelioma cure.

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 certain treatment plans.

  • 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 study, the majority of patients who survive for two years after their diagnosis have epithelioid mesothelioma.

If you have epithelioid mesothelioma, then your prognosis varies depending on whether you have the pleural or peritoneal form of this cancer:

  • 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.

Based on research, this cellular type of mesothelioma divides quickly but spreads throughout the body slower than other mesothelioma cell types. However, 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 time, such as seeing a specialist or opting for new treatments. Learn which methods mesothelioma survivors used to extend their life in our free Mesothelioma Survivors Guide.

Common Questions About Epithelioid Mesothelioma

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.

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.

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.

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: October 22, 2020.

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