Types of Mesothelioma: Comparison and Contrast

Malignant mesothelioma is an extremely uncommon and aggressive type of cancer. It is generally associated with exposure to carcinogenic fibrous minerals such as asbestos over the long term. Mesothelioma is unique in that is has an unusually long latency period, so the time from first exposure to a carcinogen to becoming symptomatic may span decades, a half a century, or longer.

What types of mesothelioma are there?

Malignant mesothelioma is the name of a specific type of cancer which may occur in the linings of the lungs (pleural mesothelioma), abdominal cavity (peritoneal mesothelioma), heart (pericardial mesothelioma) or testis (paratesticular mesothelioma). Mesothelioma cancer may also produce different cell types: epithelial mesothelioma occurs strictly in the epithelial cells of the mesothelium, whereas sarcomatoid mesothelioma manifests in lengthened, spindle-shaped cells and can be difficult to tell apart from healthy tissue and thus. Some mesotheliomas involve a combination of the two cell types, and these are called biphasic.

How do the mesothelioma types differ?

The types of mesothelioma differ in regard to which cell types they produce and affect and which parts of the body they initially afflict. Pleural and peritoneal mesothelioma may be more easy to treat than pericardial and paratesticular mesothelioma. Also, epithelial mesothelioma is generally regarded as being less difficult to treat than sarcomatoid or biphasic mesothelioma, as the shape and location of the sarcomatoid cells make them difficult to differentiate from normal, healthy cells.

How are they the same?

All types of mesothelioma have one thing in common: they are aggressive cancers. The speed at which mesothelioma tends to grow and spread is very swift compared with other forms of cancer. Also, all mesotheliomas share in the long period of dormancy—a person who was exposed to asbestos or another fibrous carcinogen as a young adult may not experience symptoms and be diagnosed until long after he or she has reached retirement age.

Pleural mesothelioma: a closer look

Pleural mesothelioma afflicts the lining of the lungs, and is thought to be caused by inhalation of asbestos or other carcinogenic fibers. It is sometimes misdiagnosed as lung cancer, or even as pneumonia based on symptoms reported prior to screening tests that show the size and location of the tumor. Making up approximately three-quarters of all mesothelioma diagnoses, pleural mesothelioma is by far the most common form of this type of cancer. Symptoms may include difficulty breathing, coughing, fluid build-up in the lungs (called a pleural effusion), and pain and pressure in the chest. Depending on the stage at which pleural mesothelioma is diagnosed, it may be treated in a variety of ways including surgery to remove the tumor, surgery to drain the lungs of fluid, radiation and chemotherapy.

Peritoneal mesothelioma: a closer look

Peritoneal mesothelioma affects the lining of the abdominal cavity, and is thought to be caused by accidental ingestion of fibrous minerals such as asbestos. It is sometimes misdiagnosed; women who have peritoneal mesothelioma may be diagnosed as having ovarian cancer if the mesothelioma has spread to the pelvic region of the peritoneum, and based on symptoms reported it may be misdiagnosed as a more benign form of gastrointestinal upset, such as irritable bowel syndrome. Symptoms may include abdominal or chest discomfort, pressure and pain, difficulty breathing, and abdominal swelling. Between 10 and 20 percent of malignant mesothelioma diagnoses are peritoneal mesothelioma, making it the second-most common type of meso.

Pericardial mesothelioma: a closer look

Pericardial mesothelioma afflicts the lining of the heart, and is one of the rarest forms of this already-rare cancer, comprising around 1 percent of all meso diagnoses. Pericardial mesothelioma is sometimes misdiagnosed as a form of heart disease such as angina based on symptoms reported. Such symptoms typically include chest pain, palpitations and difficulty breathing. Treatment for this type of mesothelioma may include chemotherapy and radiation treatments, or in some cases, surgical removal of some of the lining of the heart.

Paratesticular mesothelioma: a closer look

Paratesticular mesothelioma affects the lining of the testes, and is the rarest form of mesothelioma, making up far less than 1 percent of diagnoses with fewer than 500 cases documented worldwide to date. Symptoms tend to appear more readily than with other forms of mesothelioma and include a visible lump in the testicular area that is often painless at first. Because it can be “caught” earlier than other forms of mesothelioma, paratesticular mesothelioma can be easier to effectively treat via surgical excision of the affected tissue, generally involving removal of one testicle. Case studies have shown that, unlike other forms of meso, treatment of paratesticular meso has yielded a very low level of recurrence at the one-and-two-year marks post-treatment.