Mesothelioma cancer cell types:

Mesothelioma cells are divided into three main categories: epithelioid, sarcomatoid cells, and a mix of the two types called biphasic mesothelioma.

Epithelioid Mesothelioma

Epithelioid mesothelioma cells are the most common, found in at least half of all cases of malignant mesothelioma. It is relatively easiest to treat of all types of mesothelioma. Accounting for approximately 50% to 70% of all mesothelioma cancer cells, epithelioid mesothelioma is the most common type of histological category. Because it is the least aggressive of the cell types, it generally responds the best to treatment, and offers the best prognosis.

These cells are relatively uniform in shape and have a tubular pattern with a distinct cell nucleus when observed under microscope. The individual cells are shaped like cubes or multi-sided boxes. Because of the similarity between adenocarcinoma and mesothelioma cancer cells, they are often confused and mesothelioma can be misdiagnosed. Inspection of the cancer cells under high-powered microscopes and identification of unique characteristics of the chemical properties of the cells can help make the proper diagnosis.

Sarcomatoid Mesothelioma

The second type of mesothelioma is sarcomatoid mesothelioma. Sarcomatoid mesothelioma is the most serious form of the disease, as it rarely responds to any treatment whatsoever. Cells of sarcomatoid mesothelioma are less common, occurring only in 20 to 40% of all cases.

Sarcomatoid cells may be found in the type of malignant mesothelioma cells known as biphasic cells– a combination of sarcomatoid and epithelioid cells. Because of the similarity of appearance, the sarcomatoid cancer cells can also easily be confused with the more typical sarcoma cancer cells.

Microscopic analysis normally shows a spindle cell or storiform structure with enlongated nuclei not as apparent as in the epithelial type. Sarcomatoid mesothelioma is so dangerous because it attacks and generally arises from support tissues such as bone, cartilage, muscle, and fat. Death usually occurs within six months of diagnosis of sarcomatoid mesothelioma.

Biphasic or mixed cell type Mesothelioma

Biphasic mesothelioma is not an independent type of mesothelioma. Biphasic mesothelioma is not a condition unto itself, as the name implies, is a combination of elements of both the epithelial and sarcomatoid subtypes, with components of each in the same tumor, or found in specific groupings throughout the tumor.

Approximately 20% to 40% of the mesothelioma cancer cells fall into the biphasic category. However, recent studies have suggested that biphasic mesothelioma accounts for 46% to 63% of all mesothelioma cancer cells.

Biphasic mesothelioma is different from epithelioid and sarcomatoid mesothelioma in that it does not have a unique cellular pattern. A section of tissue examined by a histopathologist may only contain epithelioid cancer cells, leading to a misdiagnosis of epithelioid mesothelioma. Multiple biopsies can help to avoid such mistakes and help lead to a correct diagnosis of biphasic mesothelioma.