Epithelioid mesothelioma refers to a cell type found in a type of malignant cancer (mesothelioma) that forms after long-term exposure to asbestos fibers or dust. Mesothelioma can develop in the lungs, heart, or abdomen. This is a rare disease that is largely still a mystery to the medical community. Epithelioid mesothelioma makes up about 70% of all mesothelioma and is the most prevalent type of cancer cell present in biphasic mesothelioma (mesothelioma containing both epithelioid cells and sarcomatoid cancer cells). Mesothelioma originates in the body cavity in the protective lining that surrounds all internal organs and structures, including the chest and abdominal walls.
There are four types of mesothelioma, all of which may contain epithelioid mesothelioma cells:
- Pleural Mesothelioma – Pleural mesothelioma develops when epithelioid mesothelioma cancer cells grow on the protective lining surround the lungs, lining the chest walls, and all nearby structures (the “pleura”). This type of mesothelioma is found in up to 75% of all confirmed cases of mesothelioma and is the most common form of the disease.
- Peritoneal Mesothelioma – Peritoneal mesothelioma is the second most common form of mesothelioma and is a cancer containing epithelioid mesothelioma cancer cells that originate in the linings found in the abdominal cavity (the “peritoneum”).
- Pericardial Mesothelioma – Pericardial mesothelioma is the third most common form of mesothelioma and originates when epithelioid mesothelioma cancer cells grow in the protective lining around the heart (the “pericardium” or “pericardial sac”). This type of mesothelioma is very rare.
- Tunica Vaginalis Mesothelioma – Tunica vaginalis mesothelioma is the rarest of all type of mesothelioma and is hardly reported at all from a statistical standpoint. This type of mesothelioma originates in the protective lining that surrounds the testes when epithelioid mesothelioma cancer cells develop.
Epithelioid mesothelioma derives its name from the layer of cells that surrounds each internal structure. The lining surround each internal structure is known, collectively, as a mesothelium. The types of cells that comprise the mesothelium are epithelial cells; cells which have the distinct purpose of separating parts of the body. The mesothelium protects the internal organs from friction damage during breathing and other physical activity.
Epithelioid Mesothelioma Causes
Epithelioid mesothelioma cells are most likely to occur in the lungs because that is the most common organ with which asbestos fibers may come into contact. Asbestos, specifically the dust of the mineral, has long been known to cause respiratory illnesses. In the 1970’s, it was confirmed that asbestos fibers are a likely direct cause of mesothelioma.
Dust is usually inhaled by those who work closely with asbestos, however it may also be ingested through swallowing the dust or enter the blood stream when dust contaminates an open wound.
The likelihood of developing epithelioid mesothelioma cells due to asbestos exposure is related to the length and density of exposure to the mineral over a long period of time.
Epithelioid Mesothelioma Symptoms
The symptoms of epithelioid mesothelioma cells in the body vary depending on the location, number of cells (tumor size), and severity of the cancer (if it has spread or “metastasized”). Cancer that has grown to be wide-spread will cause more symptoms than in cases where the cancer is not yet wide-spread. However, even very small tumors can cause symptoms if they are growing in a sensitive area near a blood vessel or nerve.
The most general symptoms of cancer are lethargy, weight-loss, and fever. However, specific locations and large tumors can cause any of the following symptoms, depending on the part of the body cavity that is affected by epithelioid mesothelioma.
| Symptoms of Metastasized Epithelioid Mesothelioma Cells |
|---|
| Symptom | How Epithelioid Mesothelioma Cells Cause the Symptom |
| General Pain | Masses of cells (tumor) and organ failures or interruption in organ functions |
| Fever and Sweating | Particularly night sweating; caused by infection, pain, or dysfunction of organs. |
| Weight loss | Caused by pain and loss of appetite or affected organs with sasses of cells (tumor) blocking digestive passages and other organ processes. |
| Nausea and Vomiting | Caused by pain or affected organs with tumors blocking digestive passages and other organ processes. |
| Bowel Changes | Change in regularity, bowel movements; caused by blocking digestive passages and other organ processes. |
| Lumps\Bumps | Masses of cells (tumor) just beneath the skin on the lining of the abdominal and chest walls |
| Pleurisy | Masses of cells (tumor) occupying pleural space, causing effusion which makes breathing painful. |
| Chest Pain | Epithelioid mesothelioma cells applying pressure to nerves and cause effusion, even if a small tumor. |
| Dry Cough | Masses of cells (tumor) applying pressure to esophagus or lung wall. |
| Breathlessness | Masses of cells (tumor) cause effusion and block vessels\passageways. |
| Difficulty swallowing | Masses of cells (tumor) that apply pressure to blood vessels, causing swelling of esophagus. |
| Back Pain | Masses of cells (tumor) applying pressure to nerves or as a result of effusion. |
| Weight loss | Masses of cells (tumor) can cause pain, which leads to loss of appetite. |
| Hoarseness | Masses of cells (tumor) apply pressure to esophagus. |
| Swelling | Masses of cells (tumor) apply pressure to blood vessels. |
| Effusion | Epithelioid mesothelioma cells occupying pleural space, causing overproduction of serous fluids that have nowhere to go. |
Epithelioid Mesothelioma Diagnosis
Epithelioid mesothelioma must be diagnosed through a biopsy; a procedure in which a doctor takes a small sample of tissue from the site of an abnormality (tumor) and sends it to a pathology lab for further analysis. Only by viewing samples through a microscope can medical professionals deduce that epithelioid mesothelioma is present and causing the symptoms exhibited by the patient.
Under a microscope, epithelioid mesothelioma cells appear to be shaped like cubes. A clear nucleus is visible. Epithelioid mesothelioma cells look very much like adenocarcinoma, a form of cancer that may be present in the mesothelium but originates elsewhere. Close scrutiny of the sample must be coupled with any knowledge of asbestos exposure and other pathological tests to exclude adenocarcinoma as a possible diagnosis. One such test is a blood test that looks for the markers of mesothelioma in the patient’s blood.
Epithelioid Mesothelioma Treatment
Epithelioid mesothelioma cells are treated with traditional cancer treatment options. Chemotherapy and radiation are the most common follow up treatments, while surgery is the most preferred method of treatment. During surgery, doctors attempt to remove all visible traces of the cells in an attempt to rid the body of cancer and inhibit future reproduction of the cells.
Alternative treatments for epithelioid mesothelioma include a procedure known as photodynamic therapy. During photodynamic therapy, a light sensitive agent is injected into the blood stream. The photosensitizing agent remains in cancer cells for a great amount of time than healthy cells that purge the substance. Once the healthy cells have had the opportunity to shed the chemical, laser light is directed at the cancer cells. The reaction within the cell caused by the agent is effective in destroying the cells.
Gene therapy and immunotherapy are other choices for dealing with epithelioid mesothelioma, though their efficacy is debated. Mesothelioma is very resistant to traditional cancer treatments, so many types of treatment may be employed in an attempt to destroy the cancer. Combination therapies that include more than one of these treatment types may be the best way to rid the body of epithelioid mesothelioma cells.
