Types of Mesothelioma By Location & Cell Type
The types of mesothelioma are based on the location where the cancer develops and its cell type. For example, when it forms in the pleural lining around the lungs, the cancer is called pleural mesothelioma. The most common location where mesothelioma forms is in the lungs, but other locations include the abdomen, heart and testicles.
Each mesothelioma type can lead to different symptoms. Treatment is tailored by cell variety. The prognosis varies by mesothelioma tumor location, too.
Primary types of mesothelioma by location and cell type:
- Pleural mesothelioma (lungs)
- Peritoneal mesothelioma (abdomen)
- Epithelioid mesothelioma (epithelioid cells)
- Biphasic mesothelioma (epithelioid and sarcomatoid cells)
Rare types of mesothelioma by location and cell type:
- Pericardial mesothelioma (heart)
- Testicular mesothelioma (testes)
- Sarcomatoid mesothelioma (sarcomatoid cells)
- Other rare cell sub-types, including: well-differentiated papillary cells, small cell, deciduoid, cystic, desmoplastic, adenomatoid and heterologous cells.
Pleural is the most common mesothelioma. Approximately 70% to 75% of cases occur in the pleura. More research has been conducted on this mesothelioma tumor than any of the others.
Most patients qualify for chemotherapy, radiation therapy. Some may qualify for immunotherapy. These therapies can add months or years to life expectancy.
Characteristics of Pleural Mesothelioma
- Location: Pleural lining (chest)
- Symptoms: Shortness of breath, chest pain, weight loss, fever and fatigue
- Prognosis: With treatment, 3+ years at stage 1 versus 12 months at stage 4
Peritoneal disease accounts for 10% to 20% of mesothelioma cases. There is less research available on peritoneal compared to pleural; however, the prognosis for this tumor type is better.
According to research, around half of peritoneal mesothelioma patients who have surgery and heated chemotherapy (HIPEC) live five or more years after diagnosis.
Characteristics of Peritoneal Mesothelioma
- Location: Lining of the abdomen (peritoneum)
- Symptoms: Abdominal pain and swelling, bloating, loss of appetite and bowel changes
- Prognosis: 52% live at least five years after surgery with HIPEC
The pericardial tumor type is extremely rare. Around 200 cases are reported in medical literature. With surgery, some patients live for years beyond the average six-month life expectancy.
Characteristics of Pericardial Mesothelioma
- Location: Lining of heart (pericardium)
- Symptoms: Irregular heartbeat, chest pain, difficulty breathing and cough
- Prognosis: Typically ranges from six weeks to 15 months
Testicular mesothelioma develops in the lining of the testes. This form of mesothelioma is the most rare. Less than 100 cases are reported in the medical literature.
Treatment options include surgery and chemotherapy, which can help people live more than two years after diagnosis, on average.
Characteristics of Testicular Mesothelioma
- Location: Forms in the tunica vaginalis, which is the lining covering the testes
- Symptoms: Scrotal swelling, painless testicular lumps
- Prognosis: 2 years
Three Types of Mesothelioma Cells
The three mesothelioma cell varieties are epithelial, sarcomatoid and biphasic. Biphasic is a mix of the first two cell types.
Mesothelioma doctors can tell the difference between cells based on how they look under a microscope.
Different mesothelioma tumors respond differently to treatment. Epithelial or epithelioid cells respond the best, and sarcomatoid cells are more resistant to treatment.
Cancer doctors take these differences into account when planning your mesothelioma treatment. Incidence of these cell types varies by cancer location.
Epithelial Cell Mesothelioma
Epithelioid mesothelioma makes up approximately 70% to 75% of all cases of asbestos-related mesothelioma cancers.
Epithelioid cell has the best prognosis. It tends to be less aggressive and doesn’t spread as quickly as sarcomatoid and biphasic cell disease.
About 50% of pleural disease is epithelioid. Around 75% of peritoneal tumors are made up of epithelioid cells.
Sarcomatoid Cell Mesothelioma
Sarcomatoid mesothelioma is the least common mesothelioma cell category. It is the most aggressive and difficult to treat. It accounts for around 10% to 20% of all mesothelioma diagnoses.
You may hear sarcomatoid mesothelioma referred to as sarcomatous, spindle or diffuse malignant fibrous mesothelioma.
About 20% of pleural tumors are sarcomatoid, while only 1% of peritoneal mesothelioma are sarcomatous.
Biphasic mesothelioma refers to tumors that contain epithelial and sarcomatoid cells. Life expectancy after diagnosis with biphasic mesothelioma depends upon which cell predominates in the tumor.
More epithelioid cells generally mean a better prognosis. If the tumor is mostly sarcomatous, it is harder to treat and life expectancy is shorter.
Around 30% of pleural and 25% of peritoneal tumors are biphasic cell.
Prevalence of Pleural Mesothelioma Tumors by Cell Type
Prevalence of Peritoneal Mesothelioma Tumors by Cell Type
Based on the limited number of cases reported in the medical literature, pericardial mesothelioma exhibits roughly equal distribution of the three mesothelioma cell types.
Approximately two-thirds of testicular mesothelioma cases are epithelioid cell. The rest of testicular cases are biphasic. Only one case of purely sarcomatoid cell disease is reported for testicular mesothelioma.
Rare Mesothelioma Cell Types
Rare cell types of mesothelioma are typically subtypes of the common cell types: sarcomatoid, epithelioid and biphasic. These rare forms of mesothelioma may be difficult to diagnose, and have slightly different characteristics that affect the mesothelioma patient’s prognosis and life expectancy.
For example, patients with sarcomatoid tumors tend to have the shortest survival, but some patients with the lymphohistiocytoid subtype of sarcomatoid cell have survived as long as six years.
According to a 2020 study published in Translational Lung Cancer Research, researchers are debating whether lymphohistiocytoid should be reclassified as a form of epithelioid mesothelioma.
- Well-differentiated papillary cells commonly occur in peritoneal mesothelioma. Only a handful of cases have been reported in people with other mesothelioma cancer locations.
- Small cell mesothelioma is another cell type that occurs more commonly in the abdomen.
- A little more than half of the cases of deciduoid mesothelioma occur in the abdomen. Slightly less than half arise in the lung lining.
- Cystic and papillary cells are more common in peritoneal mesothelioma.
- Desmoplastic and lymphohistiocytoid are more common in pleural mesothelioma.
- Adenomatoid cells can occur in both malignant mesothelioma and benign mesothelioma.
- Heterologous cells are found in tumors that may also contain bone, cartilage and soft tissue.
Mesothelioma Treatment for Tumor and Cell Type
Your specific mesothelioma diagnosis will influence your treatment options. Different treatments may be available, depending on the location of your cancer and possibly, the cell type.
Surgical procedures to treat pleural mesothelioma include:
- Extrapleural pneumonectomy
- Pleurectomy and decortication
Peritoneal tumors are removed with a peritonectomy. Pericardial tumors are removed with a pericardiectomy. Testicular tumors are removed with an inguinal orchiectomy.
A combination of cisplatin and Alimta (pemetrexed) is the most effective regimen against pleural mesothelioma.
Combinations of gemcitabine, Alimta, mitomycin and carboplatin are most effective against peritoneal mesothelioma.
No particular chemotherapy regimen is consistently effective for pericardial or testicular mesothelioma. The two latter types of mesothelioma are so uncommon that they have not been studied enough to know which treatment is best.
In these rare situations, a mesothelioma expert oncologist can devise the best treatment plan based on their experience and your overall health.
In pleural mesothelioma, radiation therapy is used with and without surgery. Radiation therapy typically isn’t a typical treatment for peritoneal mesothelioma, but it has been used successfully to treat pericardial and testicular mesothelioma.
The goal of palliative therapy is to alleviate pain and other symptoms of the disease. Palliative care can significantly improve quality of life and well-being of mesothelioma patients.
For example, thoracentesis can be employed to drain fluid from around the lungs, and paracentesis is used to remove fluid from the abdomen. These procedures can alleviate pain and pressure and make breathing and eating easier for you.
Selecting the Right Treatment
To find the right treatment for each patient, doctors consider many factors. This includes cancer stage, cell type, a patient’s age and overall health, and the patient’s desires and needs going into treatment.
Surgery may be recommended to early-stage patients who are younger and in good health. Chemotherapy, radiation therapy and immunotherapy are available to every patient regardless of stage or age.
Common Questions About Types of Mesothelioma
- What is the difference between mesothelioma cell types and tumor location?
Tumor location refers to where the cancer first began growing such as the lining of the lungs or abdomen. Cell type refers to the type of cells that make up the tumors.
- How does the type of mesothelioma impact prognosis and treatment?
The type of mesothelioma a patient has impacts which treatments will be recommended and their overall prognosis. Mesothelioma treatment is complex, and many other factors influence treatment options and prognosis such as the stage of the cancer.
- How can I find a mesothelioma specialist for my type of mesothelioma?
You can speak with a Patient Advocate to find a mesothelioma specialist who has experience treating your type of mesothelioma.
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