About Mesothelioma Cell Types
Every case of mesothelioma is defined by the types of cells found in a tumor. Some patients have rare subtypes with unique traits that set them apart from others. Knowing the difference between rare types of mesothelioma helps doctors create a treatment plan that’s tailored to your diagnosis.
To find out which cell type you have, doctors take a biopsy and a pathologist studies the tissue under a microscope to see how the cells look and grow. This information helps your care team understand how the cancer acts and which treatments may work best for you.
There are three mesothelioma cell types:
- Epithelial (epithelioid): The most common type. These cells tend to grow in groups and spread more slowly, which means they usually respond better to surgery and chemotherapy.
- Sarcomatoid: The rarest and most aggressive form. These cells are long and spindle-shaped, so they can spread quickly and are harder to treat.
- Biphasic: A mix of epithelial and sarcomatoid cells. How this type behaves depends on which kind of cell is more dominant.
Some rare subtypes grow more slowly, while others spread in unusual ways or respond differently to treatment. Because of this, doctors often use special lab tests to confirm the exact subtype.
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Rare Epithelial Mesothelioma Subtypes
Epithelial mesothelioma is the most common form of this cancer, but there are still some rare subtypes within it. Knowing which one you have helps doctors choose the most effective treatment and helps you understand what to expect.
Here are some of the rarer epithelial subtypes:
- Adenomatoid mesothelioma: These cells form small, gland-like shapes that can look like harmless tumors. It tends to grow slowly, which can make treatment more effective when it’s caught early. Adenomatoid mesothelioma accounts for a very small percentage of pleural mesothelioma cases.
- Deciduoid mesothelioma: This type usually appears in the abdomen and shows up more in younger women. It grows faster than most epithelial subtypes, so early diagnosis really matters.
- Papillary mesothelioma: Fewer than 200 cases have been reported to date. This rare subtype is usually slower-growing than others, which may give patients more treatment options.
No two cases are exactly alike, and getting an accurate diagnosis makes a big difference. If you have epithelial mesothelioma, ask your doctor what subtype you have and what that means for your care.
Rare Sarcomatoid Mesothelioma Subtypes
Sarcomatoid mesothelioma is less common but tends to spread faster than other cell types. The cells are shaped like long spindles, which makes them tougher to identify and treat. Understanding the exact subtype can help doctors find the right approach for you.
Some of the rare sarcomatoid subtypes include:
- Desmoplastic mesothelioma: This subtype has a lot of tough, fibrous tissue that can make it hard to spot during testing.
- Lymphohistiocytoid mesothelioma: This cell subtype contains both cancer cells and immune cells, which makes it look similar to other conditions like lymphoma (a type of cancer that starts in the lymph nodes or immune system).
- Small cell mesothelioma: An extremely rare type that resembles small cell lung cancer. It grows quickly and may require a mix of chemotherapy, immunotherapy, and palliative care for symptoms.
Rare sarcomatoid subtypes make up a very small fraction of mesothelioma cases, according to a review published in Translational Lung Cancer Research. Desmoplastic mesothelioma accounts for fewer than 2% of diagnoses.
Sarcomatoid mesothelioma requires care from specialists who have seen these rare forms before. They know how to interpret test results and create the right treatment plan for you.
How Are Rare Types of Mesothelioma Diagnosed?
Getting the right diagnosis is the most important step in treatment. Imaging tests like CT, MRI, and PET scans help doctors see where tumors are, but only a biopsy can confirm mesothelioma and show which subtype it is.
Because rare mesothelioma cell types can look similar to other cancers under a microscope, pathologists use specialized tests and histology (the study of how cells and tissues look and behave under a microscope) to make sure the diagnosis is accurate.
To confirm the results, doctors may also use a special lab test called immunohistochemical staining. This test uses dyes to distinguish mesothelioma cells from other diseases and can be helpful in identifying rare subtypes.
In some cases, the cell subtype isn’t specified in the pathology report. This usually happens when the biopsy sample is too small, the tumor has a mix of different cell types, or doctors need more testing to confirm a rare form of mesothelioma.
If you’ve been diagnosed with a rare subtype, get matched with an experienced specialist today with our Free Doctor Match.
Misdiagnosing Rare Mesothelioma Cell Types
Because rare mesothelioma cell types can look like other cancers, misdiagnosis can happen. For example, desmoplastic mesothelioma can look like scar tissue, and lymphohistiocytoid mesothelioma can be mistaken for lymphoma. If your results don’t feel right or you’re not getting clear answers, it’s okay to ask for another opinion.
Here are a few steps you can take:
- Have your biopsy sample sent to a mesothelioma specialist for review.
- Visit a cancer center specializing in mesothelioma.
- Request additional testing if your diagnosis seems uncertain.
A second opinion can help confirm your diagnosis and give you access to more treatment options, including those available only in clinical trials.
Treating Rare Mesothelioma Cell Types
Treatment for rare mesothelioma cell types usually includes a combination of therapies designed to control the cancer, ease symptoms, and improve quality of life. Your exact plan will depend on your cell type, overall health, and how far the cancer has spread.
Common treatments for mesothelioma include:
- Surgery: This approach removes as much of the cancer as possible and is often recommended for patients in the early stages of the disease when mesothelioma tumors are still contained.
- Chemotherapy: Chemotherapy medications shrink tumors and kill mesothelioma cells. Different drugs can be used depending on your cell subtype and other factors. Many patients receive pemetrexed with cisplatin or carboplatin.
- Radiation therapy: Radiation targets tumors in the pleura (lining of the lungs) or peritoneum (lining of the abdomen) to shrink them and help relieve pain or other symptoms. It can also be used after surgery to lower the risk of mesothelioma coming back.
- Immunotherapy: Drugs boost the mesothelioma patient’s immune system to attack cancer cells. Several immunotherapy drugs are now widely used for mesothelioma after encouraging results in clinical trials.
- Palliative care: For some people with highly aggressive mesothelioma subtypes or in end stages of the disease, palliative treatment focuses on improving quality of life and managing symptoms.
Clinical trials are testing new drug combinations, targeted therapies, and immune-based treatments that may also lead to longer survival for patients with rare mesothelioma cell types. Working with a specialist who keeps up with the latest treatments can help you get the best care.
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Treating Epithelial Mesothelioma Subtypes
For patients with epithelial subtypes, surgery followed by chemotherapy is one of the most effective approaches, especially in stages 1 and 2.
Radiation therapy may follow surgery to reduce the risk of the cancer coming back. Patients with stage 3 or stage 4 mesothelioma may not qualify for surgery due to cancer spread, but other treatments like immunotherapy could help them live longer.
Treating Sarcomatoid Mesothelioma Subtypes
Because sarcomatoid cells are aggressive, surgery is less often an option. Chemotherapy and immunotherapy are the first-line (initial) treatments, sometimes alongside palliative care.
Participation in clinical trials is encouraged to access new therapies that may improve a patient’s survival rate and ease symptoms.
Get Help for a Mesothelioma Diagnosis
If you’ve been diagnosed with a rare type of mesothelioma, the right doctors and support can help you feel more confident about your treatment and what comes next.
Mesothelioma Hope’s dedicated Patient Advocates can:
- Explain your diagnosis and walk you through treatment options
- Connect you with top mesothelioma specialists who treat rare subtypes
- Help you pursue financial compensation for medical bills and living expenses
- Recommend mesothelioma support groups and peer mentor programs
Call us today at (866) 608-8933 or get your Free Mesothelioma Guide shipped overnight to learn how we can help you take the next step.
Rare Mesothelioma Subtypes FAQs
What do rare mesothelial cells mean?
When doctors mention rare mesothelial cells, they’re talking about cells that look or act differently from the ones usually seen in mesothelioma.
These differences are spotted under a microscope when a pathologist studies a biopsy sample. Sometimes, these cells have unusual shapes, sizes, or growth patterns that make them stand out.
Finding rare mesothelial cells doesn’t always mean the cancer is more aggressive, but it does mean your doctor will take a closer look to understand exactly what kind of mesothelioma you have.
What are the subtypes of mesothelioma?
When doctors diagnose mesothelioma, they examine a biopsy sample under a microscope to identify the cell type. While the three main types are epithelial, sarcomatoid, and biphasic, some patients have rarer subtypes that behave differently and may respond to treatment in unique ways.
Rare mesothelioma cell subtypes include:
- Adenomatoid mesothelioma: Features small, gland-like cell patterns that can resemble noncancerous tumors.
- Deciduoid mesothelioma: Contains large, rounded cells and often appears in the abdomen, especially in younger women.
- Desmoplastic mesothelioma: Characterized by dense, fibrous tissue that can make getting a diagnosis harder.
- Lymphohistiocytoid mesothelioma: Includes both cancer cells and immune system cells, which can make it look similar to lymphoma.
- Papillary mesothelioma: Forms small, finger-like projections and may be found accidentally during surgery for another condition.
- Small cell mesothelioma: An extremely rare and fast-growing form with tiny, aggressive cells.
Knowing your mesothelioma cell subtype helps doctors understand how your cancer might grow and which treatments are most likely to help.
If you’d like help understanding your pathology report or getting a second opinion, Mesothelioma Hope can connect you with local specialists. Contact us now to get started.
What is the rarest type of mesothelioma?
The rarest cell subtype of mesothelioma is lymphohistiocytoid, which falls under the sarcomatoid cell type. It’s made up of both cancerous cells and immune system cells, so it can be difficult to recognize under a microscope. Because it sometimes looks like other cancers, such as lymphoma, it’s easy to misdiagnose without review by a mesothelioma specialist.
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