In histological terms, malignant mesothelioma is divided into three
different types: epithelioid, sarcomatoid, and biphasic. Classifications
for these categories are dependent upon the shape and structure of the
cancer cells. In general, all types of malignant mesothelioma are
treated in a similar fashion, but some may be addressed more
aggressively than others if they result in a shorter
Of the three types of
malignant mesothelioma, epithelioid is the most common, occurring in
approximately 50 to 70 percent of cases. These mesothelioma cells have
been given this name because they have the appearance of epithelial
cells, which line organs and cavities throughout the human body.
Epithelioid mesothelioma cells generally feature a well-defined,
uniform shape when viewed under a microscope.
The second most common type of mesothelioma is called biphasic
mesothelioma. Accounting for roughly 20 to 40 percent of all
mesothelioma cases, biphasic mesothelioma tumors are composed of both
epithelioid and sarcomatoid cells. Instead of appearing as an even
mixture of cells, these cells are usually arranged in groups within a
tumor. Because of this factor, several samples are taken from different
locations within a tumor during the biopsy, which is done to ensure a
correct diagnosis is made.
In most cases, those
diagnosed with biphasic mesothelioma are considered to have a bleaker
prognosis than patients diagnosed with epithelioid or sarcomatoid
mesothelioma. Since biphasic tumors are generally more
treatment-resistant, this form of
malignant mesothelioma often receives more aggressive treatment than
other forms of mesothelioma.
Sarcomatoid mesothelioma is the least common of the three types of
malignant mesothelioma, accounting for roughly 10 to 15 percent of
diagnosed cases. Visible only when viewed under a microscope,
sarcomatoid cells appear as elongated spindle-shaped cells, which
feature an irregular shape and often overlap one another.
This form of
mesothelioma can be hard to diagnose because it resembles another form
of cancer. Cells affected by pulmonary sarcomatoid carcinoma are very
similar in appearance and feature other characteristics that are
indicative of malignant sarcomatoid mesothelioma as well.
For more information on
malignant mesothelioma and other diseases caused by asbestos exposure,
please visit Asbestos.com.