Types of Mesothelioma

There are three types of malignant mesothelioma, differentiated by their cell types and appearance under the microscope (their histology). These are:

* epithelial type
* sarcomatous type
* mixed epithelial and sarcomatous type

Cell types are determined by taking a biopsy specimen from the tumor. The most common kind of malignant mesothelioma appears to be the epithelial type (half the cases in one series), then mixed (in about one-third of cases) and sarcomatous. Within the tumor, there may be great variation in cell types, however. Some experts say that the more biopsy specimens taken, the greater the likelihood of calling the tumor "mixed type".
The epithelial type of malignant mesothelioma may be hard to distinguish from a type of lung cancer, and the sarcomatous form may resemble other sarcomatous-type cancers. However, special laboratory techniques can be used to confirm the diagnosis of malignant mesothelioma, which may be important for litigation purposes.

There is some evidence that the epithelial type of malignant mesothelioma is associated with a better outcome.