Epithelioid Mesothelioma

This type of cell is going to be related to roughly 70% of cancer cases when you look at mesothelioma. It is also very important to know that this is the most treatable.


What is Epithelioid Mesothelioma?

Epithelial cells in the body are very common and they are also healthy. They become dangerous when they mutate themselves into deadly epithelioid mesothelioma cells after being exposed to asbestos. Individuals with epithelioid mesothelioma have a better prognosis and more treatment options available to them vs. those that have sarcomatoid or biphasic cell types.

Epithelial cells are the most studied cell makeup of mesothelioma. Patients with this form of mesothelioma have a much better prognosis and more treatment options available— their life expectancy is also more optimistic.

Epithelioid Cell Structure

These cells make up one of the four major tissue types in our bodies. They can be found in several areas, including the lining of hollow organs and blood vessels and on the surface of our skin.

Epithelial cells can be in a single layer or several, with shapes ranging from the more common egg-shape to cube-shaped and even columnar. They often form small clusters of round or oval-shaped cells with multiple nuclei per cell.

This grouping makes identification simple, but it also slows the spread of malignant cells as they are slower to metastasize and are less resistant to treatment than other cells such as sarcomatoid.

Characteristics

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Cell Prevalence – Epithelioid mesothelioma is the most common cell type and it also has the best prognosis. You will find that it is the most common with men that are white and older than 45 years of age.

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Cell Description – These cell types have a defined elongated egg-shape to them. The visible nuclei make this cell the easiest type to distinguish.

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Cell Behavior – A tumor with these cells will grow much faster because they are going to divide very fast. They stick to each other which means it doesn’t spread as fast.

Diagnosis

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These cells account for roughly 70% of the pleural mesothelioma diagnoses and they can also be found in peritoneal diagnoses as well.

Epithelioid cells can present with a variety of symptoms, many of them nonspecific. Symptoms can be affected by the cancer’s location, the patient’s age and overall health, and the mesothelioma’s stage.

Some of the symptoms that you may experience with epithelioid mesothelioma include:

  • Shortness of breath
  • Pain in your chest or abdomen
  • Build up of fluid
  • Coughing and hoarseness
  • Fever and fatigue
  • Unexplained weight loss
  • Constipation
  • Nausea and vomiting

Cells may be found through radiology or even with pathology. Testing typically begins with imaging and radiology, such as CT scans, PET scans, MRIs, and X-rays. Blood testing comes next, identifying specific biomarkers to help determine if mesothelioma is present and to help eliminate other potential causes for symptoms. When cells are found the doctor may ask about the patient’s exposure to asbestos.

A biopsy will confirm diagnosis. This procedure can be either surgical or non-surgical; the doctor takes a sample of tissue, fluids, or both to send for analysis. Lab tests can then determine the stage, malignancy, and cell-types of mesothelioma.

If the biopsy shows that there are cancerous mesothelioma cells the doctor may use immunohistochemistry. This will be carried out in order to search for proteins that are used as markers for different types of cancer, including:

  • Antibodies including mesothelin, thrombomodulin, calretinin and WT1 which identify epithelioid mesothelioma in patients
  • Antibodies like Napsin A, CEA and surfactant apoprotein identify adenocarcinoma

Antibodies such as these and others can help pathologists and oncologists correctly diagnose diseases and confirm accuracy.

Subtypes

Scientists have identified several rare subtypes of epithelioid cells that can make up mesothelioma cases. They are going to have variations related to their sizes, shapes, and even their structure. Each subtype may respond differently to different types of treatment. Many act similarly to pure epithelioid cells, but others can negatively affect a patient’s prognosis and limit treatment options. Epithelioid Mesothelioma subtypes include:

  • Adenoid – • Adenoid epithelioid cells are found in all types of mesothelioma. Because it does look like other tumors it can be hard to diagnose a patient accurately.
    • Also referred to as glandular or micro glandular mesothelioma
    • Flat or cube-shaped cells
    • Can be benign or malignant
    • Forms in glands, such as the genital glands
  • Small Cell – Small cell mesothelioma has its own shape. You will see that it is the most common when you look at peritoneal mesothelioma. It will be the most difficult to treat.
    • Occasionally mistaken for small cell lung cancer
    • Typically contains biphasic cells, i.e. both epithelioid and sarcomatoid
    • Forms in the peritoneum and the pleura
  • Cystic – Cystic mesothelioma will be the rarest. It is found in peritoneal mesothelioma. More women will be affected by this than men.
    • Often benign, but can be malignant
    • Forms in the peritoneal or pleural cavities
    • Common in young women, particularly during child-bearing age
  • • Well-Differentiated Papillary – Papillary mesothelioma is not going to be very aggressive but it is rare and may not be seen that often. It will be seen in the peritoneum.
    • Not related to asbestos exposure
    • Slow to metastasize, life expectancy ranges from 36-180 months
    • Forms in the pleura, peritoneum, and/or genitals
  • Deciduoid – Deciduoid mesothelioma will be a rare cell when it is found in pleural mesothelioma. It is actually more common when found in peritoneal, and it will be found in roughly 50% of cases.
    • Extremely rare with a poor prognosis
    • Typically forms in the abdomen, can be found in lung lining
    • Most often found in women

Treatment

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When epithelioid mesothelioma is treated you may undergo the same treatment that you would with other types of mesothelioma. The good news is that this treatment will be a lot more effective than treatment used with other types of mesothelioma cancer. Among the types of treatment available to patients are chemotherapy and radiation, as well as surgical options. Many patients will choose a multimodal treatment plan comprised of multiple forms, or modes, of treatment.

There are a number of patients that are able to receive an extrapleural pneumonectomy, and it has been found to increase your life expectancy. You may be able to go through with pleurectomy with decortication (P/D) if the cancer has not made its way to the lung.

If you have epithelioid peritoneal mesothelioma then you might want to think about cytoreductive surgery. There are no stages with peritoneal mesothelioma. Therefore, it is always best to work with a specialist and get a second opinion.

Other treatment options such as chemotherapy and even radiation may be used. Alternative treatment like gene therapy or even intensity modulated radiation have been found to be effective.


Prognosis

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Cell type is a very important factor that can have a huge impact on a patient’s mesothelioma prognosis. Those with epithelioid mesothelioma have a better prognosis that those with biphasic or sarcomatoid cell types.

There was a study that showed that roughly 60% of those patients that have been diagnosed with epithelioid mesothelioma, and treated for it, lived for at least one year after they started their treatment. Approximately 25% were found to live for more than 5 years.

Prognosis is often determined by a variety of factors in addition to cell type. The location of the cancer, its current staging, and the patient’s age and overall health all play a role in life expectancy. The decision to pursue treatment also affects matters, often extending a patient’s life expectancy and improving their quality of life.

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