What Is Epithelial Mesothelioma?

Epithelial Cell Type of Mesothelioma.Epithelial cells are long (columnar) or square (cuboidal) and indicate a favorable mesothelioma prognosis.

Epithelial mesothelioma cancer is the most common of the disease’s three cell types. Epithelial cells line the part of the airway known as the bronchus. These cells are sensitive to asbestos exposure as the air you breathe passes into the lungs.

Epithelial mesothelioma accounts for 50% to 70% of cases. It has the best prognosis because it is the most responsive to aggressive treatment. Patients with this tumor cell type live about six months longer than those with other cell types.

Characteristics of Epithelial Cells

Epithelial mesothelioma cells clump together in groups and do not tend to travel. These cells are less likely to spread or metastasize to other areas of the body. This improves the prognosis of the epithelial type compared to sarcomatoid mesothelioma.

Epithelial malignant mesothelioma cells can take on a variety of shapes and sizes. These include cuboid (square), columnar (long) or squamous (flat). They are also characterized by a visible nucleus that contains DNA.

Symptoms of Epithelial Mesothelioma

Mesothelioma symptoms are the same, no matter the cell type. A person with the epithelial form will have similar symptoms as the sarcomatoid type. Instead, the cell type affects which treatments are most helpful.

Epithelial cell mesothelioma symptoms include:
  • Shortness of breath
  • Persistent, nonproductive (dry) cough
  • Hoarseness
  • Coughing up blood
  • Low blood oxygen levels
  • Anemia (low iron levels)
  • Fever
  • Night sweats
  • Weight loss
  • Feeling full, even without eating
  • Lack of appetite and nausea
  • Fatigue and extreme tiredness

Talk to your doctor if you experience any of these symptoms. Be as specific as possible so they can order the correct diagnostic tests for you.

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Prognosis for Epithelial Mesothelioma

An epithelial prognosis includes cancer survival rates and life expectancy. Doctors measure these from the time of diagnosis. The median survival of epithelial malignant mesothelioma patients is 18 months.

The biphasic cell type consists of a mixture of epithelial and sarcomatoid cells. Patients with this type have a median survival of about 10 months. Those with sarcomatoid type have a median survival of seven months.

“Epithelial cell type by far is the best malignant mesothelioma cell type to have. This patient will definitely have more options such as surgery and is more likely to respond to treatment. The survival rate for epithelial patients is overall significantly longer.”
Karen Selby, R.N.
Patient Advocate

Epithelial Mesothelioma Diagnosis

Diagnosing epithelioid mesothelioma requires several steps. These include imaging scans, biopsies, and blood tests. Early symptoms can include cough or shortness of breath. These signs are often vague and prompt tests to rule out other illnesses.

It’s crucial to share your history of asbestos exposure. This can alert your doctor to the need for more detailed testing. The average wait is about three months between the first symptoms and a diagnosis. By sharing your history, your doctor will likely consider an asbestos-related condition.

Challenges of Diagnosing Epithelioid Mesothelioma

When diagnosing epithelial mesothelioma, several obstacles can delay the process. After a visit to your primary doctor, they may refer you to have imaging tests done. Even with a referral, scheduling these appointments can take weeks. Imaging scans can show lung abnormalities, but they cannot diagnose cancer.

A tissue biopsy is the only way to diagnose epithelial mesothelioma. This procedure samples the lung tissue to confirm the cell type under a microscope. After imaging tests, it may take several more weeks to book a biopsy appointment.

Role of Immunohistochemistry in Epithelioid Mesothelioma Diagnosis

Immunohistochemistry (IHC) is a lab test that detects proteins on the surface of cells. This test helps pathologists classify cancer cell types.

Antibodies bind to specific proteins on the outside of epithelial cells. Some will attach to the surface, while others will not. This allows the pathologist to identify epithelial cells in different cancers.

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Epithelial Mesothelioma Cell Subtypes

After a biopsy, the pathologist will create a report for your physician. This report includes cell distribution and a final diagnosis.

The cell subtype informs your doctor how your cancer might progress. It also determines which treatment options may be best.

Tubulopapillary Mesothelioma Cell Sample
Tubulopapillary cells as seen under a microscope.

Tubulopapillary

This is the most common subtype of epithelioid mesothelioma. These cells are often well-differentiated, but doctors may mistake them for other cancers. It can appear as adenocarcinoma that has spread to the pleura.

Glandular Mesothelioma Cells
Mucus-secreting glandular cells stained for microscopic evaluation.

Glandular

Glandular tumors often develop in the pleural lining. They have a pattern made of gland-like (acinar) structures. These cells can appear like adenocarcinoma that has spread to the pleura.

Epithelial mesothelioma cells under a microscope.
Rare adenomatoid mesothelioma cell pathology.

Adenomatoid

Adenomatoid mesothelioma is also known as the microglandular cell type. It accounts for 6% of pleural mesothelioma cases. Pleural, peritoneal or pericardial mesotheliomas may all feature an adenomatoid differentiation.

These cells can occur in benign and malignant tissue. In the peritoneum, they behave as benign lesions and respond well to treatment. But, adenomatoid cells found in the pleura could be benign or malignant.

Adenomatoid mesotheliomas look like benign lesions. Doctors need to look for specific markers to differentiate between the two conditions. Doctors primarily look for pleural thickening and pleural nodules. These two characteristics are typically absent in cases of benign lesions. To diagnose lesions, doctors look for fibrous stroma (soft tissues) and bland, well-defined cell borders.

Solid Cell Variant
Pathology stain of solid epithelial cells.

Solid

There are two patterns within the solid subtype. Solid, well-differentiated epithelial type is more common. This pattern consists of round cells in nests, cords, or sheets. Poorly-differentiated cells appear unorganized with straight sides.
 
Pathologists may mistake well-differentiated cells for benign reactive mesothelial hyperplasia. The poorly-differentiated pattern looks like large cell carcinoma or lymphoma.
Deciduoid Mesothelioma Cell Type
Deciduoid mesothelioma cells stained for pathology.

Deciduoid

Deciduoid mesothelioma is a rare epithelial subtype. Doctors have diagnosed fewer than 50 cases of deciduoid mesothelioma.
 
Less than half of all deciduoid mesotheliomas are pleural, forming in the lining of the lungs. A roughly equal number of deciduoid cases occur in the peritoneum. This tissue lines the abdominal cavity. About 75% of all mesotheliomas develop in the pleura of the chest.
 
This type features large cells that are either round or have sharp borders. It can be mistaken for several other types of cancer, including squamous cell carcinoma (a type of lung cancer). It may also appear like a gastrointestinal autonomic nerve tumor or a variant of ovarian clear cell carcinoma.
well-differentiated papillary mesothelioma
Well-differentiated papillary mesothelioma.

Well-Differentiated Papillary Mesothelioma

This cell type is slow-growing and features small bumps or protrusions. A single layer of thin cells lines the border. Papillary mesothelioma is often benign and responds well to surgery. It is more common in younger and older adult women with peritoneal mesothelioma.

Epithelial Mesothelioma Treatment Options

Research shows that a combination of therapies provides the most benefit. Doctors often prescribe a mix of surgery and chemo. Of the three types, malignant epithelial pleural mesothelioma responds best to treatment.

Treatment Types and Median Survival for Epithelial Mesothelioma Patients

Treatment Type Median Survival
No Treatment 10.2 Months
Chemotherapy Alone 15.4 Months
Surgery Plus Chemotherapy 21.1 Months
Multimodal (all three) 21.7 Months
Source: The Annals of Thoracic Surgery, 2019

Patients diagnosed with the epithelial variant may also receive radiation and immunotherapy. Doctors tailor mesothelioma care to your diagnosis. Seeking a specialist is the first step in finding the best treatment. 

Common Questions About Epithelial Mesothelioma

How does a mesothelioma cell type affect my prognosis and treatment?

Patients with the epithelioid cell type have the most mesothelioma treatment options. This cell type responds the best to all forms of treatment. Epithelioid patients also live an average of 200 days longer than patients with other cell types.

How do I find a doctor who treats epithelial mesothelioma?

Most oncologists are not trained to treat epithelioid mesothelioma. Mesothelioma doctors have trained for years to specialize in the treatment of this cancer. Our Patient Advocates can help you find a top doctor who treats epithelial mesothelioma.

How can epithelial cells turn into mesothelioma?

Epithelial cells line the airways and are constantly exposed to substances from the air you breathe in. One of the main causes of mesothelioma is asbestos exposure. When you inhale asbestos fibers, they can become trapped in the lungs and induce inflammation. Long-term inflammation can lead to mutations in epithelial cells, eventually giving rise to cancer.

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