Epithelioid mesothelioma represents about 70 percent of all mesothelioma cell types. It is also the least lethal type of mesothelioma and is more associated with a longer lifespan when compared to biphasic or sarcomatoid mesothelioma.
Understanding Epithelioid Mesothelioma
Epithelioid mesothelioma is derived from epithelial cells, which are the cells lining many body tissues. These are cube-shaped cells when they are in their normal state. When they mutate (change) to become cancerous cells, sometimes the cube shape is maintained while sometimes the shape is altered. Epithelioid mesothelioma tends to be found more often in pleural disease and among men who are more than 45 years of age.
Even though this cell type divides more quickly than the other mesothelioma cell types, the cells tend to stick to one another so that metastases are less common. Instead there is greater growth at the original site of the cancer.
Signs and Symptoms of Epithelioid Mesothelioma
People with epithelioid mesothelioma tend to get these symptoms:
- Chest pain at the site of the tumor
- Fluid around the lung tissue
- Shortness of breath
- Unexplained weight loss
Doctors use different techniques to try and identify the source of these symptoms, eventually arriving at the correct diagnosis of the disease.
Subtypes of Epithelioid Mesothelioma
Among epithelioid mesotheliomas, there are different subtypes that should be explained on the pathology report. These are the subtypes you might want to look for:
- Tubulopapillary subtype. This is a common subtype of epithelioid mesothelioma. It looks like tiny tubules with cells shaped like cubes that look mostly similar to one another. Inside the cells, tiny nucleoli are seen that are about medium-sized. The cells are usually relatively mature, meaning they don’t grow as fast as other cancer cell types. Because of its appearance, it can mimic adenocarcinoma of the lung so doctors must be careful to take all factors into consideration before deciding that this is epithelioid mesothelioma.
- Adenomatoid subtype. This accounts for only about 6 percent of all mesotheliomas found in pleural tissue. It is also called the microglandular subtype. The cells look like cubes that are arranged in the shape of tiny glands. It looks a lot like other cell types, such as metastatic cancer that has gone to the pleura so that it is sometimes difficult to diagnose under the microscope.
- Solid subtype. This subtype can be very mature or very immature. The mature type is very commonly seen in mesothelioma. Cells form small nests or sheets of cells. The nucleoli within the nucleus of the cells are large. If this subtype is immature, it looks more disorganized and the cells are rounder. The immature type of solid epithelioid mesothelioma often looks a lot like lymphoma, a type of blood cancer.
- Glandular subtype. These are cells shaped like glands. The cells are cube-like in shape and are usually found in the lungs. It often looks like metastatic adenocarcinoma of the lungs.
- Deciduoid subtype. This subtype is relatively rare. It has round or polygonal-shaped cells with a large amount of intracellular fluid in the cells. The nucleoli inside the nucleus of the cells of this subtype tend to be large. It is often mistaken for squamous cell cancer of the lungs or large cell lymphoma, among others.
Treatment of Epithelioid Mesothelioma
Because epithelioid mesothelioma has the best prognosis, doctors use aggressive therapies to try and slow the progression of the disease. Common surgeries for epithelioid mesothelioma include:
- Extrapleural Pneumonectomy—this is when the plural lining, the entire lung, and parts of the diaphragm and pericardium are removed. This is the most radical type of pleural mesothelioma surgery.
- Pleurectomy with decortication—In this case, the pleural lining containing the cancer cells is removed; the lung and other nearby areas are not removed as part of this procedure, so the patient recovers faster.
- Cytoreduction—this is used in peritoneal epithelioid mesothelioma and is often combined with HIPEC, which involves putting heated chemotherapy agents inside the peritoneal space.
Surgery is often combined with radiation therapy and chemotherapy, designed to get rid of any unseen cancer cells and to prolong the patient’s life.
Prognosis of Epithelioid Mesothelioma
People with epithelioid mesothelioma live on average about a year after being diagnosed with the cancer. While this isn’t the best prognosis, it can mean living several years if the disease is diagnosed early enough at a low stage. Statistics tell us that 60 percent of all patients with this type of cancer are still alive after one year post-diagnosis. A full 25 percent of all patients can manage to live past the five-year mark.
The prognosis is believed to be in part due to cell type. Epithelioid cell mesothelioma is considered the best cell type to have, which accounts for patients with this cell type living longer than those with sarcomatoid or biphasic mesothelioma.