Biphasic Mesothelioma

Biphasic mesothelioma is a combination of epithelioid and sarcomatoid mesothelioma cells. This type of mesothelioma is the second most common cellular diagnosis. A patient’s prognosis heavily depends on the ratio of epithelioid to sarcomatoid cells.


Written by Jenna Campagna, RN


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What Is Biphasic Mesothelioma?

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Biphasic Cell Type

Biphasic mesothelioma tumors are made up of both epithelioid mesothelioma and sarcomatoid mesothelioma cells. Biphasic mesothelioma accounts for between 20 and 30 percent of cases.

For a mesothelioma diagnosis to qualify as biphasic, both cell types must account for at least 10 percent of the cells. If the minority cell type accounts for less than 10 percent of the cells, then the disease is diagnosed as the majority type.

Tumors with a higher epithelioid mesothelioma cell ratio typically grow faster but do not spread as fast. Biphasic tumors with a higher sarcomatoid mesothelioma cell ratio spread faster through the body.

Characteristics of Biphasic Cells

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Cell Description

A biphasic diagnosis involves a mixture of the other two mesothelioma cell types. This means the patient’s prognosis depends on which cell is more prevalent. More epithelioid cells for the patient equals a better prognosis.

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Cell Behavior

The behavior of a biphasic diagnosis is dependent on the ratio of cells. A mesothelioma with more sarcomatoid cells will spread quicker than a mesothelioma with more epithelioid cells.

Biphasic Mesothelioma Symptoms

Biphasic mesothelioma symptoms resemble those of epithelioid mesothelioma and sarcomatoid mesothelioma. The symptoms vary depending on if the disease is pleural or peritoneal.

Symptoms of biphasic pleural mesothelioma include:

  • Pain in the chest or lower back
  • Difficulty breathing and swallowing
  • Coughing
  • Pleural effusions (fluid buildup in the pleura)

Symptoms of biphasic peritoneal mesothelioma include:

  • Abdominal pain
  • Ascites (fluid in the abdomen)
  • Constipation
  • Nausea


Doctors use a technique called immunohistochemistry to diagnose mesothelioma. Once a biopsy is performed and tissue removed, experts coat the cells with dye to make the proteins in the cells more visible. These proteins are used as markers to detect if cancer is present.

Specialists are extremely important for diagnosing mesothelioma because treatment can vary depending on which cell type (epithelioid or sarcomatoid) is most prominent.


Treatment for biphasic mesothelioma includes chemotherapy, radiation and surgery. New treatments, such as gene therapy and immunotherapy, are having a positive effect on patients with this cellular type of mesothelioma.



For early-stage pleural biphasic patients, the main surgical options are extrapleural pneumonectomy and pleurectomy with decortication. For early-stage peritoneal biphasic patients, the primary surgery is cytoreduction with heated intraperitoneal chemotherapy (HIPEC). Doctors will take the ratio of cells into account when determining if surgery is an option.

Receiving a correct diagnosis is important for the patient to get the best treatment possible. Some types of mesothelioma treatment are not performed on biphasic patients if the percentage of sarcomatoid cells is greater than epithelioid cells.


Chemotherapy, Radiation and Emerging Methods

The newest pathology recommendations state that biphasic mesothelioma patients shouldn’t be excluded from receiving chemotherapy. The report also states that these patients should be eligible for clinical trials, which could test emerging treatment methods like immunotherapy, gene therapy, virotherapy and more.

Depending on where the cancer forms, biphasic mesothelioma patients may also receive radiation. This treatment is usually combined with surgery or chemotherapy.

Misdiagnosis of biphasic mesothelioma is common because the cancer is so rare. Patients should seek the knowledge of a mesothelioma specialist. Get in touch with a specialist for a second opinion using our free Doctor Match program.


Patients with a biphasic mesothelioma largely comprised of epithelioid cells tend to have a better prognosis than those with mostly sarcomatoid cells.

A study published in the Annals of Surgical Oncology showed how cytoreduction and HIPEC is used for biphasic peritoneal mesothelioma patients. The median survival time was 6.8 years for patients who underwent a complete resection.

Another report in the Annals of Surgical Oncology showed the survival times for biphasic pleural mesothelioma patients who underwent surgery. The median overall survival for the 354 patients analyzed was 15.8 months.

A 2018 study in Clinical Lung Cancer shows the average survival time for each mesothelioma cell type:

  • Biphasic patients lived for an average of 9.5 months following their diagnosis.
  • Epithelioid patients, by comparison, survived for 14.5 months on average.
  • Undergoing surgery lengthened the average survival time by around six months for biphasic and epithelioid patients.

There have been cases of biphasic mesothelioma patients living longer than the average survival rate. Receiving treatment from a mesothelioma specialist is the most effective way to improve a prognosis.

Common Questions About Biphasic Mesothelioma

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What does biphasic mesothelioma mean?

Biphasic mesothelioma is a combination of both epithelioid cells and sarcomatoid cells. For a case to constitute formally as biphasic mesothelioma, it must consist of at least 10% of both types of cells. The physical appearance of biphasic mesothelioma depends on the ratio of epithelioid cells to sarcomatoid cells.

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How common is biphasic mesothelioma?

Biphasic mesothelioma accounts for between 20% and 30% of all mesothelioma cases. It can occur in both pleural mesothelioma and peritoneal mesothelioma, although it’s more likely for the former.

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How long do people with biphasic mesothelioma live?

The average life expectancy for biphasic mesothelioma is 9-10 months following diagnosis. Surgery can extend a patient’s life by a few months, or even multiple years. The prognosis also depends on whether the cancer consists of more epithelioid cells or more sarcomatoid cells.

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How is biphasic mesothelioma treated?

Treatment for biphasic mesothelioma depends on which cell type makes up the majority of cells in the tumors. If the cancer is mostly epithelioid cells, then doctors may use surgery since they’ll be able to remove them easily. If the biphasic mesothelioma is made up mostly of sarcomatoid cells, then palliative treatments are offered.

Last Edited: January 15, 2021.

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