Mesothelioma information centre

Mesothelioma (pronounced mee-so-thee-lee-oma) is a cancer of the mesothelium. The mesothelium is a thin membrane that lines the chest and abdomen and surrounds the organs in these areas. The lining around the lungs is called the pleura and in the abdomen it is known as the peritoneum.

Mesotheliomas are uncommon cancers, although they are becoming more frequent. Currently, about 1800 people in the UK are diagnosed with mesothelioma each year.

Mesothelioma of the lining of the lungs (pleural mesothelioma) is much more common than mesothelioma in the peritoneum. For every person with peritoneal mesothelioma there will be about 12 people who have pleural mesothelioma.

Peritoneal mesothelioma

The lining of the abdomen is known as the peritoneum. It also has two layers: the inner (visceral) layer, which is next to the abdominal organs; and the outer (parietal) layer, which lines the abdominal wall.

If the mesothelioma is in the peritoneum it is called peritoneal mesothelioma and causes thickening of the membranes surrounding the abdominal organs and a collection of fluid in the abdomen. The collection of fluid is called ascites and causes swelling of the abdomen.

A diagram of the side view of the abdomen showing the peritoneum