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Mesothelioma Cell Types infographics showing Three cell types side by side, with Sarcomatoid in the middle as the largest and the other two in smaller circles to the left and right, epithelioid and biphastic.

Types of Mesothelioma Cells

Generally, the types of mesothelioma cells can be significant in a patient’s prognosis and cancer treatment plan. About 60 percent of all mesothelioma (a form of cancer caused by asbestos exposure) cases are epithelioid. This cell type usually has a better prognosis than sarcomatoid, which accounts for about 25 percent of all cases. The remaining 15 percent of cases are biphasic, meaning a patient’s tumor exhibits both epithelioid and sarcomatoid cells. A biphasic diagnosis requires at least 10 percent of each cell pattern to be present in the tumor.

Epithelioid tumors originate in the cells that line an organ, whereas sarcomatoid tumors start growing in the bone or soft tissues. Sarcomatoid cells tend to metastasize faster than epithelioid cells, making epithelioid cases generally more treatable. Most patients with epithelioid tumors undergo a multimodal treatment plan (treatment approach that combines multiple therapies, such as chemotherapy and radiation) to eradicate their cancer.

It’s also important to remember that statistics are merely that: statistics. Statistics are numbers based on other patients, other circumstances of asbestos exposure, and other survival rates. And because mesothelioma is a rare form of cancer, these numbers are usually stale. As a patient, attitude matters. Accepting your mesothelioma diagnosis doesn’t mean you must accept your doctor-given prognosis. Many patients have outlived their original prognosis, and treatment options continue to advance as doctors learn more about this rare disease.

Epithelioid Sarcomatoid Biphasic (mixed)
60% of cases 25% of cases 15% of cases
18-24-month median survival 4-6-month median survival 10-15-month median survival

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How Do I Know What Cell Type I Have?

A biopsy is the only definitive way to confirm a mesothelioma diagnosis and will help your doctor determine what cell type you have, so she can plan the best course of treatment.

Mesothelioma histology requires the study of cancerous mesothelial cells. Your doctor will consult with a histopathologist (i.e., a doctor specializing in the study of diseased cells). They will examine the sample of diseased tissue from the biopsy, analyzing the cell structure to determine the type of cells present in the tumor. This information is critical for doctors when crafting a specialized treatment plan.

A histopathologist uses an additional set of diagnostic tests, called immunohistochemistry, or IHC, to diagnose a patient’s mesothelioma cell type. IHC uses antibodies or matching molecules that attach to different cell markers, proteins that classify and identify cells. Specific enzymes are then added to the section of diseased tissue to produce different colors. These color changes help doctors further visualize and identify various tissue abnormalities and can lead to a more precise diagnosis.

Epithelioid Mesothelioma Cell Type

Epithelioid mesothelioma is the most common type, accounting for more than 50% to 70% of cases. These mesothelioma cells are uniform, sharply defined, and range from square to tubular in shape. They feature prominent nuclei and divide quickly, but they tend to stick together, meaning they take longer to spread throughout the body. Epithelial cells, in particular, tend to respond more favorably to certain therapies, potentially influencing a prognosis positively. with a better prognosis and a median survival time of 18-24 months. Epitheloid mesothelioma treatment often includes a combination of therapies, such as chemotherapy and radiation, to which this cell type is typically the most responsive.

Sarcomatoid Mesothelioma Cell Type

Sarcomatoid mesothelioma is less frequent, comprising roughly 10% to 20% of cases. Sarcomatoid cells are spindle-shaped, lack a defining structure, and have an irregular configuration. They spread faster than epithelioid cells because they don’t stick together as they grow. This makes sarcomatoid mesothelioma more aggressive and harder to treat. It often forms less clear-cut tumor boundaries, complicating surgical interventions. As a result, sarcomatoid mesothelioma is typically diagnosed at a more advanced stage, with fewer treatment options available and a poorer prognosis, reflected in a median survival time of 4-6 months.

Biphasic Mesothelioma Cell Type

Biphasic mesothelioma combines both epithelioid and sarcomatoid cells, accounting for at least 10% of the tumor mass. This mixed cell type represents around 20% to 30% of mesothelioma cases. The prognosis for biphasic mesothelioma depends on the proportion of each cell type present, with better outcomes when there are more epithelioid cells and fewer sarcomatoid cells. Treatment options, including surgery, chemotherapy, and radiation, are tailored based on the dominant cell type and its aggressiveness. The life expectancy for biphasic mesothelioma patients varies accordingly, with more epithelioid cells generally leading to a longer life expectancy.

Exclusive Interview about Mesothelioma Biopsy Sampling Errors

Vijayalaksmhi Ananthanarayanan, MD, a surgical pathologist at Loyola University Medical Center, specializes in diagnosing patients with mesothelioma. She looks at different cell sites to stage the disease and determine how far it has spread and uses that information to confirm or disagree with the original diagnosis. Although a biopsy is necessary to confirm mesothelioma, it’s not always a foolproof method.

“There’s always a question of sampling error,” Ananthanarayanan told Mesothelioma Hub. “While it looks like epithelioid mesothelioma in a biopsy, you could end up falling in a section where it could be biphasic or even sarcomatoid. We are not always able to call mesothelioma in a biopsy. Despite the biopsy being a gold standard, you can still have the sampling errors, where what has been sampled is not representative of the actual lesion.”

 

Video Transcript

“There’s always a question of sampling error. When you get biopsies they are either needle or small biopsies from thoracoscopic biopsies. While it looks like epithelioid mesothelioma in a biopsy, you could end up falling in a section where it could be biphasic or even sarcomatoid. There is always a sampling error, so I think that is important. We are not always able to call mesothelioma in a biopsy and despite the biopsy being a gold standard, you can still have the sampling errors, where what has been sampled is not representative of the actual lesion.” Dr. Vijayalakshmi Ananthanarayanan, Surgical Pathologist, Loyola University Medical Centers

What to do After you Know Your Mesothelioma Cell Type

Knowing your mesothelioma cell type allows you to actively participate in discussions about your treatment and healthcare. Our patient advocate team is ready to assist you by connecting you with a legal or medical specialist who can explain your specific cell type, answer your questions, and guide you through the next steps. The type of mesothelioma cells you have – epithelioid, sarcomatoid, or biphasic – significantly influences your treatment plan, impacting prognosis and available options. Don’t hesitate to get in touch with us today for assistance.

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