Types of Epithelioid Mesothelioma

Epithelioid mesothelioma is the most common of three mesothelioma cell types and accounts for 50 to 70 percent of all mesothelioma diagnoses. It acts as an umbrella category for a number of other mesothelioma subtypes. Some subtypes, such as tubulopapillary and solid variant mesothelioma, are relatively common and account for a large portion of epithelioid diagnoses. Others, on the other hand, are documented only a few times and lack a significant amount of research.
Epithelial tumors tend to show more uniform patterns than non-epithelial tumors. Because of their structure, tumors tend to respond better to treatments like surgery. Better response overall means patients receive better prognoses and live longer.
Because all epithelioid types have uniform cell structures, the particular cell type of a patient's cancer may not drastically alter treatment options or survival rates. The table below lists all the types of epithelioid mesothelioma.

Types of Epithelioid Mesothelioma

• Adenoid
• Histiocytoid
• Single File
• Adenomatoid/Glandular
• In Situ
• Small Cell
• Clear Cell
• Macrocystic
• Solid Variant
• Deciduoid

• Cystic
• Microcystic
• Tubulopapillary
• Diffuse
• Mucin Positive
• Well Differentiated Papillary
• Gaucher Cell-Like
• Poorly Differentiated
• Glomeruloid
• Signet Ring

Defining Characteristics of Types of Epithelioid Mesothelioma

Malignant mesothelioma cancer, of which there are three primary types, has its general characteristics. So, too, do the types of epithelioid mesothelioma have their defining characteristics. Some types develop in different places in the body than others. Some are highly rare, others much less so. Here are the primary defining characteristics of each epithelioid subtype.
Every year, upwards of 3,000 people pass away from mesothelioma in the United States. Many of these people are employed in similar industries that have used asbestos for numerous years. A few industries that have a history of employees developing malignant mesothelioma include the shipyard, construction and automotive industry. Because workers in these industries were usually male, more men have been diagnosed with the illness than women.

Adenomatoid Mesothelioma

• Also called glandular because of a gland-like appearance
• Usually develops in the pleural lining
• Accounts for 6 percent of all pleural mesothelioma cases
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Small Cell Mesothelioma

• Made up of small cells that form sheets
• Usually develops in the peritoneum
• May be mistaken for small cell lung cancer
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Cystic Mesothelioma

• Subtypes: multicystic, adenoid cystic, macrocystic and microcystic
• Usually develops in the peritoneum
• May be benign or cancerous
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Deciduoid Mesothelioma

• Uncommon, 45 cases ever reported
• Might be caused by factors other than asbestos exposure
• Primarily develops in the peritoneum and pleura
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Solid Variant Mesothelioma

• Can be well differentiated or poorly differentiated
• Made up of round or polygonal cells

Well Differentiated Mesothelioma

• Also called well differentiated papillary mesothelioma
• Usually develops in the peritoneum
• Uniform appearance
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Clear Cell Mesothelioma

• Very rare
• Made up of clear, polygonal cells
• Often confused for other illnesses (e.g. renal cell carcinoma)

Glomeruloid Mesothelioma

• Uncommon cell type
• May not be linked to asbestos exposure
• Made up of round or oval-shaped cells

Mesothelioma In Situ

• Refers to mesothelioma found before it has formed
• Effectively a Stage 0 diagnosis
• Virtually impossible to diagnose alone

Mucin Positive Mesothelioma

• Accounts for 2 to 5 percent of epithelial mesothelioma cases
• Determined by staining patterns
• Diagnosed by the presence of mucin

Diffuse Mesothelioma

• Subtypes: pleomorphic, solid, micropapillary, tubulopapillary and trabecular
• Usually develops in the pleura, occasionally develops in the peritoneum
• Made up of many small, shiny, whitish nodules

Gaucher Cell-like Mesothelioma

• Also called glandular because of a gland-like appearance
• Usually develops in the pleural lining
• Accounts for 6 percent of all pleural mesothelioma cases

Glomeruloid Mesothelioma

• Uncommon cell type
• May not be linked to asbestos exposure
• Made up of round or oval-shaped cells

Histiocytoid Mesothelioma

• Very rare
• Made up of cells that resemble pulmonary alveolar macrophages

Poorly Differentiated Mesothelioma

• Also called pleomorphic mesothelioma
• Develops in the pleural lining
• Made up of large cells that are round, polygonal or irregularly shaped

Signet Ring Mesothelioma

• Rare type
• Usually develops in the peritoneum
• May be mistaken for signet ring carcinoma

Single File Mesothelioma

• Cells are arranged in a single file pattern
• May be mistaken for metastatic lobular carcinomas of the breast

Tubulopapillary Mesothelioma

• One of the most common epithelioid subtypes
• Usually develops in the peritoneum
• Made up of relatively uniform cells

Mesothelioma Etiology

Etiology research is used to determine what causes a particular disease. Mesothelioma researchers study the characteristics of patients who have been diagnosed with the illness to establish what factors may cause the cancer.
Results of previous etiology studies have discerned that a large percentage of mesothelioma cases can be linked to asbestos exposure. Once asbestos fibers become lodged in the healthy cells of the body, they may create a genetic change that results in the formation of tumors.

Prevention and Mesothelioma

Although not everybody who is exposed to asbestos will contract the illness, the only guaranteed way to prevent the cancer is to avoid exposure to this carcinogen. While the combined effects of asbestos exposure and smoking may increase a person’s chance of developing mesothelioma, a healthy and active lifestyle can help prevent the disease.

Get Regular Screenings

Because asbestos is the primary catalyst for the development of mesothelioma, anyone who has been exposed in the past should receive regular screenings. People who are at a higher risk for the illness should be aware of the symptoms and immediately discuss any health changes with a doctor. If you are concerned about being at risk for mesothelioma and would like assistance with finding a specialist in your area, the Mesothelioma Center’s Doctor Match Program can help you find the right medical care.
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