What is pleural mesothelioma?

More than 2,500 people are diagnosed with mesothelioma in the UK each year.

Mesothelioma is a cancer of the mesothelium. This is a thin lining (membrane) that covers the outer surface of most of our body’s organs. The mesothelium has different names in different parts of the body. In the chest it’s called the pleura. 

In the abdomen it’s called the peritoneum.

Cancer of the mesothelium is called malignant mesothelioma. However, it’s usually referred to simply as mesothelioma.

There are two main types of mesothelioma: pleural mesothelioma and peritoneal mesothelioma. Pleural mesothelioma is much more common than peritoneal mesothelioma.

The pleura has an inner and outer layer. The inner layer covers the lungs, and the outer layer lines the ribcage.

The pleura produces a fluid that acts as a lubricant, which helps you to breathe easily and allows the lungs to move in and out smoothly.

When mesothelioma develops in the pleura, the layers of the pleura thicken and press inwards on the lung. Fluid may also collect between the two layers. This is called a pleural effusion.

Structure of the lungs and pleura
Structure of the lungs and pleura

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Cell types of mesothelioma

Mesothelioma can be grouped according to how the cells look under a microscope. There are three main types:

  • epitheloid – this is the most common
  • sarcomatoid (fibrous)
  • mixed (biphasic) – this has both epitheloid and sarcomatoid cells.

Knowing the type of cell involved may give your doctors an idea of how well the disease will respond to treatment.

Back to Understanding pleural mesothelioma

What is cancer?

Cancer starts in cells of our body. Sometimes, cells go wrong and become abnormal. These cancer cells keep dividing to make more and more abnormal cells.