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Important Facts About Epithelioid Mesothelioma
- Epithelioid mesothelioma is a commonly diagnosed cell type for this cancer, as it is present in 70% of cases.
- There are many mesothelioma treatment options available for epithelioid mesothelioma patients.
- Patients with this cell type typically have promising survival rates, especially following successful mesothelioma surgery.
What Is Epithelioid Mesothelioma?
Epithelioid Cell Type
Epithelioid mesothelioma, a subtype of the rare cancer mesothelioma, is the result of mutated mesothelial cells. Specialists analyze the cells to determine the mesothelioma cell type present in the patient’s body, which can be epithelioid, sarcomatoid or a combination of both (biphasic).
Mesothelial cells genetically mutate due to irritation caused by exposure to asbestos, which is the only known cause of mesothelioma. Once asbestos fibers enter the body, the toxic particles can become lodged in the mesothelium, which is the lining of the lungs, abdomen and heart.
The mesothelium is made up of healthy epithelial cells, which means irritation of the mesothelium impacts the epithelial cells. Diseased epithelial cells of the mesothelium can turn into mesothelioma tumors.
Patients with epithelioid mesothelioma often have a better prognosis and more treatment options than people with sarcomatoid mesothelioma or biphasic mesothelioma. Epithelioid cells are easy to identify and remove during surgery. They also metastasize (spread) slower.
Characteristics of Epithelioid Mesothelioma Cells
Epithelioid mesothelioma accounts for between 50% and 70% of mesothelioma cases.
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.
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 of adenocarcinoma, which is a type of cancer forming in organs like the lungs, colon and breast. Symptoms of epithelioid mesothelioma are dependent on where the mesothelioma forms, such as pleural mesothelioma (in the lining of the lungs) or peritoneal mesothelioma (in the lining of the abdominal cavity).
Epithelioid pleural mesothelioma symptoms include:
- Shortness of breath
- Chest or lower back pain
- Difficulty swallowing
- Arm or face swelling
- Pleural effusions
Epithelioid peritoneal mesothelioma symptoms include:
- Abdominal pain
- Ascites (fluid in the abdomen)
- Bowel issues
Epithelioid Mesothelioma Diagnosis
In order to diagnose epithelioid mesothelioma, doctors will first perform a biopsy to extract tissue from the area where the cancer has formed. For instance, in cases of epithelioid pleural mesothelioma, doctors will take a biopsy from the lining of the lungs. In cases of epithelioid peritoneal mesothelioma, the biopsy will be taken from the lining of the abdomen.
Once the tissue biopsy is performed, doctors begin the process of histology, which is the microscopic study of tissue samples for the presence of cancer. After histology tests confirm the presence of cancer, the test results are provided through a pathology report, which identifies the specific types of cells found in the samples.
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 include:
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)
Shown in between 70% and 95% of cases
Demonstrated in between 90% and 100% of cases
Treatment Options for Epithelioid Mesothelioma
Epithelioid mesothelioma often has more treatment options than the other mesothelioma cell types. The primary treatment options for epithelioid mesothelioma are surgery, chemotherapy and immunotherapy. However, many factors can affect a patient’s specific treatment plan, especially the type of mesothelioma. For instance, epithelioid pleural mesothelioma and epithelioid peritoneal mesothelioma are treated differently.
Subtypes of Epithelioid Mesothelioma
Subtypes of epithelioid mesothelioma 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.
The five subtypes are:
- Small cell
Epithelioid Mesothelioma Prognosis
The prognosis for epithelioid mesothelioma is typically the best out of the other cell types. An epithelioid mesothelioma prognosis can range from 10-20 months. According to the Orphanet Journal of Rare Diseases, most patients who survive for two years after their diagnosis have epithelioid mesothelioma.
Patients with epithelioid mesothelioma can have varying life expectancies. Epithelioid pleural mesothelioma is more common than epithelioid peritoneal mesothelioma. However, epithelioid peritoneal mesothelioma usually has a more promising prognosis than epithelioid pleural mesothelioma.
An epithelioid mesothelioma prognosis is determined by many factors, but the main factor to consider is whether the patient has been diagnosed with pleural or peritoneal:
- According to a study published on UpToDate, epithelioid pleural mesothelioma patients survived for an average of 19 months.
- Epithelioid peritoneal mesothelioma patients survived for an average of 55 months.
Other factors, like age, stage of mesothelioma and overall health, can impact a 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. Connect with one of our patient advocates, registered nurse Karen Ritter, at firstname.lastname@example.org for help finding a mesothelioma specialist or clinical trial.
Frequently Asked 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?
There are typically more treatment options available for epithelioid mesothelioma. The cells stick together, which helps doctors remove large chunks of cells and tumors during surgery. Chemotherapy, immunotherapy, radiation, tumor treating fields and other options are all used to treat epithelioid mesothelioma.
Sources & Author
- About Malignant Mesothelioma. American Cancer Society. Retrieved from: https://www.cancer.org/content/dam/CRC/PDF/Public/8733.00.pdf. Accessed: 10/01/19.
- Epithelioid Cell. ScienceDirect. Retrieved from: https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/epithelioid-cell. Accessed: 10/04/19.
- Mesothelioma versus adenocarcinoma. Pathology Outlines. Retrieved from: http://www.pathologyoutlines.com/topic/pleuramesovsadeno.html. Accessed: 04/17/19.
- Signs and Symptoms of Mesothelioma. American Cancer Society. Retrieved from: https://www.cancer.org/cancer/malignant-mesothelioma/detection-diagnosis-staging/signs-symptoms.html. Accessed: 10/04/19.
- Immunohistochemistry. National Cancer Institute. Retrieved from: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/immunohistochemistry. Accessed: 10/04/19.
- Guidelines for Pathologic Diagnosis of Malignant Mesothelioma. International Mesothelioma Interest Group. Retrieved from: https://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2017-0124-RA. Accessed: 10/04/19.
- Long-term survival outcomes of cytoreductive surgery and perioperative intraperitoneal chemotherapy: Single-institutional experience with 1225 cases. Journal of Surgical Oncology. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/31309588. Accessed: 07/29/19.
- Malignant mesothelioma. Orphanet Journal of Rare Diseases. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2652430/. Accessed: 10/04/19.
- Malignant Pleural Mesothelioma. Edited by Kenneth O’Byrne and Valerie Rusch. Oxford University Press. 2006.