What Is Sarcomatoid Mesothelioma?
Sarcomatoid mesothelioma describes a type of malignant mesothelioma tumor that is made up of the sarcomatoid cells.
Malignant mesothelioma tumors may have one of the following cell types:
- Sarcomatoid: The least common mesothelioma cell type is sarcomatoid. It is also the most difficult to treat.
- Epithelial: The most common and treatable cell type of mesothelioma is epithelial (also called epithelioid).
- Biphasic: A mixture of the two cell types, biphasic mesothelioma’s rarity falls somewhere between sarcomatoid and epithelial.
Like the other mesothelioma cells, the only known cause of sarcomatoid mesothelioma is asbestos exposure.
Sarcomatoid cells are shaped like a spindle, similar to a long cylinder. Instead of remaining in place, sarcomatoid cells tend to move around the body easily and quickly, leading to earlier distant metastases.
Metastasis is the spread of cancer to distant parts of the body. Once the spread occurs, mesothelioma becomes harder to treat.
In addition to spreading easily, sarcomatoid cells look like other tissue cells, often leading to a misdiagnosis. Misdiagnosis allows the aggressive sarcomatoid mesothelioma to advance rapidly before a correct diagnosis can be confirmed and doctors can treat the cancer.
- According to the American Cancer Society, about 10%-20% of mesothelioma cases are sarcomatoid. They are usually pleural.
- According to a 2015 study published in The American Journal of Surgical Pathology, sarcomatoid peritoneal mesothelioma is extremely rare, with under 30 cases ever reported.
- The same American Journal of Surgical Pathology study found that the median age of diagnosis for sarcomatoid peritoneal mesothelioma was 66.
- According to the same study, the average patient lifespan from the time of diagnosis was only 5 months.
Subtypes of Sarcomatoid Mesothelioma
Sarcomatoid mesothelioma has several different sub-types. Regardless of subtype, however, patients often have a poor prognosis and rapid cancer progression.
Learn more about rare subtypes of sarcomatoid mesothelioma below.
This type is very rare, accounting for less than 1% of patients with sarcomatoid mesotheliomas. It is still characterized by the spindle shape, but its cells are more plump or rounded. Because of this, it can sometimes be misdiagnosed as epithelial mesothelioma.
This type also accounts for less than 1% of sarcomatoid mesotheliomas. It usually forms in the pleura, or the membrane surrounding the lungs and thorax. It is made up of epithelial cells and immune cells. These immune cells can be both lymphocytes and plasma cells. Life expectancy is anywhere from two-20 months.
This type of sarcomatoid mesothelioma makes up 5% of sarcomatoid mesotheliomas. It does not have a defined pattern or form. It is most common in the pleura, the membrane surrounding the thorax and lungs. It is also found in the peritoneum and testes. Life expectancy is about 3.8 months.
There are very few proven treatment options for patients with any of the sub-types of sarcomatoid mesothelioma.
Sarcomatoid Mesothelioma Symptoms
There are several different symptoms that people experience from sarcomatoid mesothelioma. These mesothelioma symptoms usually take between 20 and 50 years to develop.
You can have this type of cancer for many years before exhibiting any symptoms.
Most people who fall victim to sarcomatoid mesothelioma are in their 60s or older.
Different symptoms can be felt depending on where the sarcomatoid mesothelioma is located. If the patient is diagnosed with malignant pleural mesothelioma, it will impact the lungs and chest wall.
More rarely, mesothelioma will form in the abdominal lining, calling for a diagnosis of sarcomatoid peritoneal mesothelioma.
Early major symptoms that patients may experience include:
- Chest pain
- Shortness of breath
Because these symptoms are common to many diseases and illnesses, many patients do not get diagnosed right away based on these symptoms alone.
Other, more specific symptoms may develop over time.
Other symptoms may include:
- Blood in feces or vomit
- Bloody sputum (saliva/mucus mixture)
- Coughing up blood
- Decreased appetite
- Pain in the shoulders
- Rib pain
- Severe coughing
- Weight loss
- Vomiting blood
- Upper back pain
Most symptoms of sarcomatoid mesothelioma are the same as other types of mesotheliomas. Shortness of breath is reported in all cases of mesothelioma.
However, nausea and vomiting seem to be particular to sarcomatoid mesothelioma.
Sarcomatoid Mesothelioma Diagnosis
It can be difficult to make a sarcomatoid mesothelioma diagnosis. This tumor takes decades to become evident after initial contact with asbestos.
Early detection is difficult because the patient is typically asymptomatic (has no symptoms), or presenting symptoms that are the same as other more common illnesses.
Most patients begin the process of diagnosis when they go to the doctor for shortness of breath or chest pain.
If exposure to asbestos fibers is suspected, doctors may order tests, or they can order tests to exclude other diagnoses than mesothelioma.
Sarcomatoid mesothelioma diagnostic tests may include:
- Chest X-rays
- Computed tomography scans (CT scans)
- Positron emission tomography (PET) scans
- Magnetic resonance imaging (MRI)
- Blood tests
Blood tests look for biomarkers that help to distinguish the diagnosis of sarcomatoid mesothelioma from other disorders.
Biopsies can also be taken from different parts of the body to look at different cells and their makeup.
Sarcomatoid mesothelioma is primarily diagnosed by a tissue biopsy.
Mesothelioma pathologists (doctors specializing in diagnosing mesothelioma through biopsies) may use immunohistochemistry or other biopsy examination techniques to find antibodies unique to the sarcomatoid cell type.
Studies have shown that a biopsy that tests positive for protein calretinin and D2-40 with the antibody pancytokeratin often means sarcomatoid tumors.
From this, mesothelioma doctors can also determine the cell type and stage of the disease.
Sarcomatoid Mesothelioma Misdiagnosis
Sometimes sarcomatoid mesothelioma is misdiagnosed as something else.
It is commonly misdiagnosed because sarcomatoid mesothelioma may present with non-specific symptoms or findings. Many different illnesses and diseases can look sarcomatoid even on pathology.
Some common sarcomatoid mesothelioma misdiagnoses include:
- Fibrous pleurisy
- Fibrous tumors
- Metastasized renal sarcoma
- Non-Hodgkin’s lymphoma
- Pleural liposarcoma
- Sarcomatoid carcinoma
- Soft tissue sarcomas
A mesothelioma misdiagnosis is very dangerous because it prevents patients from getting the right treatments to extend their lives.
Sarcomatoid Mesothelioma Prognosis
The prognosis (disease outlook) for patients with sarcomatoid mesothelioma is not as good as it is for mesothelioma patients with other cell types.
A mesothelioma prognosis may vary depending on the general age, gender, and health of the patient.
It also depends on the stage of mesothelioma when diagnosed. A patient who is diagnosed early will have better treatment options and results than a patient diagnosed in the latter stages of the disease.
Sarcomatoid mesothelioma patients show a life expectancy of 1-28 months. The median life expectancy is around 6 months.
The prognosis for this type is so poor because the cells quickly travel and spread to other parts of the body.
There are also very few treatment options, meaning a patient can do little to extend their median survival.
Sarcomatoid Mesothelioma Treatment
Sarcomatoid mesothelioma is one of the most difficult types of mesothelioma to treat.
The cells are resistant to many mesothelioma treatments, and they spread quickly throughout the body, making removal through surgery nearly impossible.
However, there are still several treatment options open to patients with sarcomatoid mesothelioma.
The type of treatment doctors choose depends largely on the stage and location of the sarcomatoid mesothelioma, as well as the overall health of the patient.
Some patients may be able to withstand a more aggressive treatment than others.
Mesothelioma chemotherapy is often the first choice for treating sarcomatoid mesothelioma. It is fast-acting and can be effective in slowing or stopping progression during treatment.
In some studies, 13% of patients with sarcomatoid mesothelioma responded positively to chemotherapy treatment. In other types of mesothelioma, the rate is 21%.
Chemotherapy is used because it can treat the sarcomatoid mesothelioma cells throughout the entire body.
Radiation therapy for mesothelioma is also used in some patients. It is often used as a palliative (symptom-reducing) treatment to shrink the sarcomatoid mesothelioma cells.
It is not very effective at slowing or stopping cell growth or movement. However, it can be helpful in improving symptoms and making the patient more comfortable, leading to a higher quality of life.
Surgery is used to treat sarcomatoid mesothelioma in patients that present with the disease in just a few places within the body.
It is not typically a very effective treatment, however, because sarcomatoid cells spread quickly throughout the body. It is difficult to remove all of the spindle cells through surgery.
However, if diagnosis happens early and the cells have not spread throughout the body, surgery may be a viable option. Surgery options for eligible patients with pleural sarcomatoid mesothelioma include extrapleural pneumonectomy and pleurectomy with decortication.
Studies of new treatments for sarcomatoid mesothelioma are currently being done, often focusing on immunotherapy.
Memorial Sloan Kettering Cancer Center in New York is currently running eight different clinical trials of different drugs to treat sarcomatoid mesothelioma.
The University of Chicago, in collaboration with the National Cancer Institute, is in phase 2 of sarcomatoid mesothelioma treatment as well.
According to the National Center for Biotechnology Information, medical specialists are conducting ongoing research in other treatment types.
Other treatment options for sarcomatoid mesothelioma may include:
- Viral introduction therapies
- Cancer vaccines
- Antibody therapies
Doctors will be able to determine the right treatment or clinical trials for patients, depending on the stage and location of the malignant sarcomatoid mesothelioma.
Patients should also speak with an experienced mesothelioma attorney to learn more about paying for treatments.
Hope for Victims of Sarcomatoid Mesothelioma
A mesothelioma diagnosis affects more than just your health. It can touch just about every area of your life.
Sarcomatoid mesothelioma is the most difficult type of mesothelioma to treat.
However, new treatments and clinical trials may give hope to sarcomatoid mesothelioma victims and their loved ones.
Our team has helped hundreds with mesothelioma find top doctors, get information on treatment options, and more. Download our free mesothelioma guide today.