Mesotheliomata may be pleural, peritoneal, or pericardial. Malignant pleural mesothelioma is an aggressive neoplasm of the serosal lining of the pleural cavity, which arises from undifferentiated mesothelial cells representing the adult remnants of the surface celomic mesoderm. Mesothelial cells may give rise to both the lining epithelial cells (which express Keratin) and the paucicellular submesothelial layer. The etiology of mesothelioma is primarily associated with environmental factors, particularly exposure to asbestos and smoking. The latency period can be 10–20 years.
Epithelioid (the most common)
Sarcomatous (a much more aggressive form)
Biphasic or mixed (a combination of both of the other cell types)