Pseudomyxoma peritonei is pronounced ‘sue-doh-mix-oh-muh pary-ih-ton-nee-i’ and is often abbreviated to PMP. In most cases, it starts in the appendix; more rarely, it can start in other parts of the body such as the bowel, an ovary or the bladder. It affects around two people per million each year of all ages, both men and women.
A tumour develops in the appendix from a polyp which is a small growth on the inner lining of your appendix. At this early stage, the tumour is rarely discovered as it doesn’t cause any symptoms. Left untreated, the tumour grows and eventually bursts through the wall of the appendix into your abdominal cavity where more tumours then develop. These tumours then secrete a jelly-like substance called mucin which accumulates in your abdominal cavity. It is this build up of mucin that causes symptoms, the abdomen swells leading to the characteristic ‘jelly belly’ and vital organs are compressed.