What Is Epithelial Mesothelioma?

Epithelial, or epithelioid, mesothelioma cancer is the most common of this cancer’s three cell types. The epithelium is a protective layer of cells that line the outer surface of organs, blood vessels and cavities. Asbestos fibers irritate these cells and are the primary cause of epithelioid mesothelioma.

Critical Facts About Epithelial Mesothelioma
  • About 54% of pleural mesothelioma tumors contain epithelial cells.
  • Doctors diagnose 1,500 to 2,100 epithelioid mesothelioma patients annually.
  • Epithelial mesothelioma accounts for 50% to 70% of all cases.
  • Epithelioid cells comprise about 75% of peritoneal mesothelioma tumors.
  • The epithelioid type has the best prognosis of all types of mesothelioma.

Epithelial mesothelioma can develop in the lining of the lungs (pleural), abdomen (peritoneal), heart (pericardial) or testes (testicular). Patients with the epithelial tumor cell type live about six months longer than those with biphasic or sarcomatoid cell types. Epithelial cells respond better than others to aggressive treatment.

“The epithelial type does tend to be more favorable,” mesothelioma specialist Dr. Andrea Wolf of Mount Sinai Hospital told The Mesothelioma Center at Asbestos.com. “It does tend to respond to chemotherapy a little more easily.”

What Causes Epithelial Mesothelioma?

The primary risk factor and cause of epithelioid mesothelioma is the same as other cell types of mesothelioma: asbestos exposure. Inhalation or ingestion of asbestos fibers causes tissue inflammation and DNA damage, leading to cancer development decades later.

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

Most people diagnosed with epithelioid mesothelioma worked with asbestos products long before their diagnosis. All mesothelioma cell types have a latency period of 20 to 60 years. The first symptoms may not show up for decades after the initial asbestos exposure. 

The Patient Advocates at The Mesothelioma Center say many newly diagnosed patients who call to ask questions about their mesothelioma diagnosis typically do not know their cell type. It’s important to ask your doctor about cell type because it will help you understand your symptoms, treatment and prognosis.

Epithelioid Mesothelioma Symptoms

Epithelioid mesothelioma symptoms often include cough, shortness of breath and lack of appetite. As the disease progresses, more severe symptoms may surface. Many symptoms depend on tumor location and size.

Common Symptoms of Epithelioid Mesothelioma
  • Abdominal pain or bloating
  • Bowel or bladder changes
  • Chest tightness or pain
  • Cough, hoarseness or difficulty swallowing
  • Difficulty breathing
  • Fever or night sweats
  • Fluid buildup in the chest or abdomen (effusion)
  • Nausea, vomiting or diarrhea
  • Unexplained weight loss

Mesothelioma symptoms are the same, no matter the cell type. A person with epithelial tumors will have symptoms similar to those with the sarcomatoid type. However, the cell type affects which treatments are most helpful. Talk to your doctor if you experience any of these symptoms.

Survivor Story
Christine S. Mesothelioma Survivor

Facing Epithelial Malignant Mesothelioma

Survivor Story

Christine S. was diagnosed with epithelial malignant mesothelioma on October 11, 2007. She underwent multiple courses of chemotherapy, including six rounds of chemo with Alimta, which helped shrink her cancer. Throughout her journey, she emphasized the importance of seeking advice from medical professionals and coming to terms with her diagnosis.

Read Christine’s Story

How Is Epithelioid Mesothelioma Diagnosed?

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. Epithelial mesothelioma cells clump together in groups and do not tend to travel. These cells are less likely to spread to other areas of the body.

Critical Facts About Diagnosing Epithelial Mesothelioma

“Epithelial subtype mesothelioma describes the type of cells the pathologist is seeing under the microscope when they look at a patient’s tumor,” Dr. Andrea Wolf noted. 

Epithelial mesothelioma cells can take on a variety of shapes and sizes. These include cuboid (square), columnar (long) or squamous (flat). The cells also carry DNA within a visible nucleus. 

Understanding Your Pathology Report

After a biopsy, the pathologist will create a report for your physician. This report includes cell distribution and a final diagnosis. The pathology report describes the types of mesothelioma cells found in a patient’s tumors. The cell type informs your doctor how your cancer might progress. It also determines which treatment options may be best.


“When I first speak with a patient, I ask about their diagnosis and cell type,” Patient Advocate Danielle DiPietro noted. “If they say they don’t know, I explain how to find it on their pathology report. I also explain the three cell types and their meaning for their mesothelioma journey.”

Epithelial Cell Subtypes

Pathologists use chemical stains to reveal immunohistochemical markers and identify subtypes. If you have a specific subtype, it could influence your treatment options or mesothelioma prognosis. Rare subtypes could lead to a misdiagnosis. Some epithelioid cell subtypes, such as adenomatoid, are associated with better survival. Epithelial subtypes include:

  • Adenomatoid. Also known as the microglandular cell type, it accounts for 6% of pleural cases. The peritoneal form behaves like benign lesions and responds well to treatment.
  • Deciduoid. Doctors have diagnosed fewer than 50 cases of this rare subtype. It can be mistaken for other cancers, including squamous cell lung cancer.
  • Glandular. Glandular tumors often develop in the pleura and have gland-like (acinar) patterns. These cells mimic adenocarcinoma that has spread to the pleura.
  • Small Cell. Small cell mesothelioma does not display the stream, ribbon or rosette patterns of small cell lung cancer. This cell type has a survival rate of about eight months.
  • Solid. Well-differentiated solid cells group in nests, cords or sheets and look like benign hyperplasia. Poorly differentiated cells may look like large cell carcinoma or lymphoma.
  • Tubulopapillary. This common epithelial subtype can appear as adenocarcinoma in the pleura. It is not the same as benign well-differentiated papillary mesothelioma.
Cell Subtypes of Epithelial Mesothelioma

“When I speak with a patient who is hesitant to have a biopsy, which is rare, I explain that knowing the cell type is imperative when assessing treatment options,” DiPietro said.


Talk to your mesothelioma doctor about your cell type, cancer stage and tumor grade (speed of tumor growth). Ask how these factors affect your treatment plan and prognosis.

What Is the Survival Rate for Epithelial Mesothelioma?

The 5-year survival rate for epithelioid pleural mesothelioma is 12%. A peritoneal mesothelioma study showed a median survival of 55 months for patients with epithelioid cells. By comparison, patients with sarcomatoid or biphasic cells had a median survival of seven to 13 months.

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

Epithelioid patients live 200 days longer on average than patients with other cell types. The life expectancy of epithelial malignant mesothelioma patients is 18 months. The overall survival of all cell types drops when the disease metastasizes or spreads.

How Is Epithelioid Mesothelioma Treated?

Doctors treat early-stage epithelioid mesothelioma aggressively with surgery, chemotherapy and radiation therapy. Late-stage cases respond better to palliative care with immunotherapy, chemotherapy and Tumor Treating Fields therapy. A combination of approaches is often the most effective method.

  • Chemotherapy. Chemotherapy can triple the mesothelioma survival rate.
  • Immunotherapy. Immunotherapy can extend survival to 18 months for many patients.
  • Radiation. Radiation therapy helps manage symptoms and prevent local recurrence.
  • Surgery. Surgery extends survival an average of two years or five years after HIPEC.

Your treatment will depend on the cancer stage, tumor extent and overall health. Of the three cell types, epithelial mesothelioma responds best to treatment. 

Consider a second opinion at a top cancer center. The specialists at these centers have the experience to diagnose and treat epithelioid mesothelioma effectively. They can offer clinical trials and multidisciplinary treatment to control the disease with different therapies.

Common Questions About Epithelioid Mesothelioma

Where can I get treatment for epithelial cell mesothelioma?

Look for mesothelioma specialists with years of experience treating pleural and peritoneal mesothelioma. Most oncologists need to be trained to treat epithelioid mesothelioma. Our Patient Advocates can help you find a top doctor who treats epithelial mesothelioma.

Can epithelioid mesothelioma be prevented?

Asbestos exposure is the primary cause of mesothelioma. Avoiding it is the best way to prevent mesothelioma. If you have a history of asbestos exposure, talk to your doctor about cancer screenings, which may aid in an early diagnosis.

Is epithelioid mesothelioma curable?

Unfortunately, epithelioid mesothelioma has no cure. But patients with the epithelioid cell type have the most mesothelioma treatment options. This cell type responds the best to all forms of treatment.

Is there any ongoing research on epithelioid mesothelioma?

Researchers are constantly looking for mesothelioma patients with the epithelioid cell type for clinical trials. They seek out these participants because epithelioid is the disease’s most common cell type. Studying epithelioid patients lets researchers know how a drug or therapy will affect most patients diagnosed with mesothelioma.

How can epithelial cells turn into mesothelioma?

Epithelial cells line the airways and are constantly exposed to substances from the air you breathe. 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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