Types of Mesothelioma

Types of Mesothelioma

Let's first go back to basic terms associated with mesothelioma. Basically, every cancer, starts from the tumor mass in our bodies.A tumor is caused by body tissues that grow to form an abnormal mass. There are two basic types of tumors.

• Benign type is a non-cancerous type of tumor.
• Malignant is a cancerous type of tumor.

The terms tumor and cancer are sometimes used synonymously which can be misleading. A tumor does not necessarily mean a cancer. The term tumor simply refers to a mass. It is helpful to keep these distinctions clear when we are discussing a possible cancer diagnosis.

The term cancer refers to a new growth which will invade surrounding tissues, metastasize (spread to other organs) and may lead to the patient's death if untreated. The word cancer in Latine means crab. Like a cancer, a crab grabs onto something and will not let go.


Benign Mesothelioma is a tumor usually localized in the mesothelial layer around the lungs, heart, stomach or elsewhere in the abdomen and grows larger. However, it is not cancerous and rarely spreads to nearby tissues or other body areas. Benign mesothelioma symptoms are often similar to those of other types of mesothelioma. Treatment for benign mesothelioma tumor is usually surgery. The tumor responds very well to treatment. However, if left untreated, it can lead to a serious disease.

Malignant mesothelioma is a general term that means the mesothelioma is a cancerous type. All forms of cancer are malignant.


Based on cancerous cell types, mesothelioma is mainly classified into epithelioid, sacromatoid and mixed/biphasic.

• Epithelioid mesothelioma type is the most common form of mesothelioma cancer cells and accounts for about 50-70 percent of all people diagnosed with mesothelioma. It has the most positive prognosis (chance of recovery) among all other types, because it may grow slower and is more likely to respond to treatment. This form of mesothelioma targets the thin membrane surrounding the body's internal organs and surfaces.
• Sarcomatoid mesothelioma type is more aggressive and affects the body's secondary tissues - muscles, bones, fats and cartilage. It is found in about 7-20 percent of all mesothelioma cases and has a worse prognosis. It generally does not respond well to therapy.
• Mixed / biphasic mesothelioma type accounts for approximately 25-30 percent of all diagnosed mesothelioma cases and contains both sarcomatoid and epithelioid types. This mesothelioma type has an intermediate prognosis.

Another classification of mesothelioma cancer is based on the areas /parts of the body affected by the disease . There are four main types of mesothelioma.


Pleural mesothelioma
This type of mesothelioma cancer is the most common since it affects the pleural region of the chest cavity. Pleural Mesothelioma cancer makes up nearly 75 percent of all Mesothelioma diagnosed cases. This disease usually strikes the pleural cavity located between the thin membranes surrounding the lungs, causes pressure on it and trouble breathing as fluid builds in the chest cavity and the pleural lining thickens. That diminishes the lungs' air capacity and normal contraction and expansion functions.

Peritoneal mesothelioma
Another, second most common type of mesothelioma cancer is the peritoneal mesothelioma cancer, accounts around 20 percent of all mesothelioma cases. This disease affects the peritoneum lining of the abdominal cavity, gastrointestinal tract, bowel, liver and spleen, causing a build up of fluid in the abdominal cavity as cancerous cells spread. The lining surrounding vital organs in the abdominal area cannot function normaly and patients who suffers from peritoneal Mesothelioma cancer can experience symptoms of pain or swelling in the abdomen, anemia, breathing difficulty, blood clotting, or restriction of properly bodily functions like digestion and bowel movements.

Pericardial mesothelioma
Pericardial mesothelioma is the rarest type of the three main mesothelioma cancers and affects the pericardium, the protective sac that covers the heart and the major arteries and veins. The pericardium normaly provides constant lubrication so that the heart can function properly. Pericardial mesothelioma is more rare than pleural or peritoneal mesothelioma forms, but it is in the same time more dangerous. Often this type of mesothelioma cancer is discovered too late for treatment, and even when detected early only few treatment methods exist. Symptoms include coughing, heart palpitations, shortness of breath, irregular heartbeat and chest pains .

Testicular mesothelioma
Testicular mesothelioma cancer, has been reported in less than 100 cases. Unfortunately, this means that there are no common symptoms reported across these cases. Discovering lumps on the testicles and the swelling of the scrotum often lead to a testicular mesothelioma diagnosis.


Early detection of Mesothelioma is very important
All types of mesothelioma are hard to detect during their early stages of the disease, so the earlier that mesothelioma is detected, the more treatment options are available. Early detection can provide quicker treatment and disease management, as well as the greatest chance at a better quality of life. All types of mesothelioma cancers are very difficult to diagnose, in a large part because they mimic the normal symptoms of other more common diseases. Surgery is typically performed to remove the cancerous mass. Patients may also undergo radiation and chemotherapy to reduce or eliminate the remaining cancer mass, although in many cases the mesothelioma is deeply entrenched in the tissue and cannot be completely removed.


There are some other forms of mesothelioma, which are very rare, such as Papillary mesothelioma. Deciduoid mesothelioma, cystic mesothelioma, etc.

We will present them in the next few articles.

What is mesothelioma

Mesothelioma (malignant mesothelioma) is an aggressive uncommon form of cancer that develops from transformed cells originating in the mesothelium*. Most cases of mesothelioma occur in the chest (pleural mesothelioma), rarely may occur in the abdomen (peritoneal mesothelioma) or other organs. It is usually caused by exposure to asbestos, especially blue asbestos. Exposure may only be brief and there may be a lag-time of 20 to 40 years. Your risk is greater if you were exposed to large amounts of it from an early age for a very long period of time. But some patients say they have no history of any heavy exposure to asbestos. On every 10 people diagnosed with mesothelioma, about 80% say they have been in previous exposure to asbestos.

While mesothelioma is most common in the lungs (~90%), it's important to differentiate between lung cancer and mesothelioma. They are two very different types of cancer and require different types of treatment.

Pleural mesothelioma is the only known pleural cancer and is caused by asbestos exposure in nearly all cases. Of patients with pleural malignant mesothelioma, about 77% have been exposed to asbestos in the past. Early diagnosis is difficult because the results from fluid analysis of the tumor effusion are not usually diagnostic.

Wide range of occupations, notably railway engineering, shipbuilding and asbestos product manufacture, are associated with an increased risk of mesothelioma.

When someone is exposed to asbestos particles in the air, that will increases the risk of developing malignant mesothelioma. Most of patients who develop malignant mesothelioma in the past work on jobs where they inhaled asbestos, or were exposed to asbestos fibers and dust in other ways. Also has been suggested that washing clothes of a family member who worked with asbestos dust or fibers increases their risk for developing malignant mesothelioma. Unlike lung cancer (1.37 million deaths worldwide), there seems to be no association between malignant mesothelioma and uses of tobacco, but smoking increases the risk of other asbestos-induced cancers. Some patients who were exposed to asbestos have collected damages for asbestos-related disease (including mesothelioma). Asbestos workers have up to a 10% lifetime risk of developing the disorder, with an average latency of 30 yr. Mesothelioma can spread locally, but also can metastasize to the hilar and mediastinal lymph nodes, pericardium, peritoneum, diaphragm, kidneys, adrenals, liver and, infrequently to the tunica vaginalis of the testis.

Mesothelioma is more common in males than in females, probably because many cases have been caused by exposure to asbestos at work. It occurs most between the ages of 60 and 79 years (average age at diagnosis is 62 years of age )

Annually it's diagnosed on approximately 2,000 to 3,000 individuals in the US** comprising around .3 percent of all cancer diagnoses , most of whom die within 2 years of the diagnosis (summary by Bott et al., 2011). Unfortunately, long-term survival is uncommon.

The most common body location for the development of mesothelioma is the pleura (the outer lining of the lungs and internal chest wall), but it can also arise in the peritoneum (the lining of the abdominal cavity), and the pericardium (heart sac), or the tunica vaginalis (a sac that surrounds the testis).

Mesothelioma exists in four stages. Depending on the stage of the disease, there are various treatments available to help patients or at the very least relieve pain and improve their comfort and quality of life.

Tumor predisposition syndrome may contribute to the development of malignant mesothelioma upon asbestos exposure and is caused by germline mutation in the BAP1 gene on chromosome 3p21.

Class action lawsuits or compensation via asbestos funds is an important issue in law practices regarding malignant mesothelioma. Finding the right mesothelioma attorney and filing a lawsuit is a serious thing for you and your family, and that will increase your chances of winning a settlement in a court of law.

*Mesothelium is a protective membrane, made up of two thin layers that forms the lining of several body cavities: peritoneum (abdominal cavity including the mesentery), the pleura (thoracic cavity), and pericardium (the sac that surrounds the heart). Also, mesothelial tissue surrounds the male internal reproductive organs and covers the internal reproductive organs of women. Mesothelium that covers the body walls is called the parietal mesothelium, while the layer that covers the internal organs is called visceral mesothelium. When cancer develops in the mesothelium it's between these layers. Mesothelioma is very difficult to diagnose in its early stages, because of the narrow space in the mesothelium.

**In the UK around 2,400 people are diagnosed with mesothelioma each year.