This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on September 12, 2022.
Mesothelioma is a type of cancer that begins in the lining of certain organs, such as the abdomen or lungs. This lining is called mesothelium, and it plays an important role in producing lubrication that helps the organs move against one another properly.
There are four main types of mesothelioma:
Each type of mesothelioma may have different types of cancer cells, which may be epithelioid, sarcomatoid (or fibrous) or a mix of both types.
Mesothelioma types differ based on where the tumor first develops. Discussions between patients and their care teams about their mesothelioma diagnosis should include where the cancer originated and what that means for treatment options.
The most common type of mesothelioma is pleural mesothelioma, which accounts for about 82.1 percent of cases, according to the U.S. Centers for Disease Control and Prevention (CDC). It begins in the chest cavity lining that surrounds the lungs. Prior exposure to asbestos, a mineral fiber that was formerly used in construction and is now a known carcinogen, is the biggest risk factor for this disease.
Symptoms may include:
Some people might not notice any symptoms.
Treatment options may include:
These treatments may help patients manage the disease and live as long as possible. In some cases of early-stage disease, surgery may also be an option, but the benefits are still under debate.
According to the American Cancer Society, pleural mesothelioma has a five-year survival rate of 20 percent for localized cancers and 12 percent for all stages combined. But each patient’s circumstances differ.
Peritoneal mesothelioma begins in the tissue that surrounds the abdomen. It’s the second-most common type of mesothelioma (after pleural mesothelioma), accounting for 9.9 percent of all cases, according to the CDC. The biggest risk factor for this disease is also exposure to asbestos.
Peritoneal mesothelioma doesn’t always have obvious symptoms, which means it may sometimes be hard to diagnose. However, when patients do experience symptoms, they typically include:
Because the disease is so rare, limited studies have been performed on possible treatment options. Currently, surgery and chemotherapy are the two most widely used treatments. Survival rates for this cancer type vary based on the types of cells found in the cancer and the patient’s age.
Pericardial mesothelioma is a rare type of mesothelioma that begins in the pericardium, which is the lining around the heart. According to the CDC, it accounts for about 0.2 percent of all new mesothelioma cases.
This mesothelioma type may also be hard to diagnose, and it doesn’t always have clear symptoms. When symptoms occur, they may include:
Small tumors may sometimes be removed surgically. Other treatment options include chemotherapy and radiation therapy.
This cancer is often diagnosed at an advanced stage. The median survival time from diagnosis has been reported as six months, according to a 2019 review in Clinical Lung Cancer.
Testicular mesothelioma (also known as tunica vaginalis mesothelioma) is another rare type of this disease. It originates in the layers covering the testicle. According to the CDC, it accounts for fewer than 1 percent of all mesothelioma cases (about 0.2 percent).
Symptoms may include an enlarged scrotum, sometimes with fluid.
Due to the disease’s rarity, there’s no standard treatment for testicular mesothelioma, but treatment may include surgery, chemotherapy and radiation therapy.
With so few cases diagnosed, survival data is based on a very small group of patients. A 2019 study in Urology notes that the five-year survival rate was 49 percent among a group of 113 patients.
In addition to the types of mesothelioma mentioned above, three types of cells are found in mesothelioma cancers:
Each cell type responds differently to treatment, which is why it’s important to know which type of cells have been detected at diagnosis.
Epithelioid cell mesothelioma accounted for approximately 69 percent of cases among 1,183 patients in a 2015 study in the Journal of Surgical Research. These cells tend to grow more slowly and respond well to treatment.
Sarcomatoid cell mesothelioma, which is less common than the epithelioid type, accounted for about 19 percent of cases in the Journal of Surgical Research study. These cells don’t always respond well to chemotherapy, so this type of cancer may be more difficult to treat.
Biphasic cells, which are a mix of epithelioid and sarcomatoid cells, accounted for about 12 percent of cases in the Journal of Surgical Research study. This cancer type is easier to treat than sarcomatoid cells alone, but it doesn’t respond as well to treatment as epithelioid cells alone.
Next topic: What are the stages of mesothelioma?