Mesothelioma is a cancerous tumour of the mesothelium that can grow into and destroy nearby tissue. It can also spread (metastasize) to other parts of the body. The mesothelium is the lining that covers the outer surface of most of the internal organs. It may be called different names, depending on what organ it is covering.
Pleural mesothelioma starts in the membrane that covers the lungs, called the pleura. It is the most common type of mesothelioma. More men than women are diagnosed with pleural mesothelioma.
Peritoneal mesothelioma starts in the peritoneum, which lines the inside of the abdomen and covers many of the organs in the abdomen. This is the 2nd most common type of mesothelioma. Men and women are equally affected by peritoneal mesothelioma.
The following cancerous tumours of the mesothelium are very rare.
Pericardial mesothelioma starts in the sac surrounding the heart (the pericardium). The most common symptoms of pericardial mesothelioma are heart problems caused by the tumour or buildup of fluid around the heart. These include chest pain, chest pain that gets worse with deep breathing or coughing, problems breathing, and feeling anxious or restless. Another symptom is palpitations, where the heart feels like it is fluttering, pounding or racing. Treatment may include surgery, radiation therapy or chemotherapy. Pericardial mesothelioma has a very poor prognosis (predicted outcome).
Mesothelioma of the tunica vaginalis starts in the layer that covers the testicles (the tunica vaginalis). The most common symptoms are pain and swelling of the testicle. Treatment is surgery to remove the testicles and the scrotum and the lymph nodes in the area. Radiation therapy may be offered after surgery. The role of chemotherapy in treatment of mesothelioma of the tunica vaginalis isn’t known because the disease is very rare.
Mesothelioma cell types
Mesothelioma can also be described by the cell makeup of the tumour, as seen when looked at under a microscope. There are 3 main cell types of mesothelioma.
Epithelioid is the most common mesothelioma cell type. This type has a more favourable prognosis than the other cell types.
Sarcomatoid, also called fibrous, is the 2nd most common mesothelioma cell type. This type of cell spreads more quickly than epithelioid cells.
Mixed, or biphasic, have both epithelioid and sarcomatoid areas within the tumour. Tumours with more epithelioid cells have a better prognosis than tumours with more sarcomatoid cells.