Symptoms and causes of pseudomyxoma peritonei (PMP)

By Jeyashree Sundaram, MBA

Pseudomyxoma peritonei (PMP) normally starts as a slow-growing tumor in the appendix and it is hence classified as a low-grade mucinous appendiceal neoplasm (LAMN). In rare incidences, it may develop in other organs, such as the ovary, bowel, or the bladder.    

Credit: Sebastian Kaulitzki/

PMP is an uncommon disease that is characterized by the aggregation of mucinous ascites inside the peritoneal cavity. As the mucin develops in the lining of the tummy, it results in the compression of the bowel and other intestinal organs. It affects women more than men, with a ratio of 9:1.


PMP symptoms typically take a long time to appear and some patients do not show any of the symptoms for a number of years. As a result, this deadly disease can be difficult to diagnose. The symptoms include:

  • Abnormality of the abdomen, the abdominal wall, and the peritoneum:


  1. Swelling of the abdomen
  2. Abdominal pain
  3. Irritation
  4. Redness


Increased size of the abdomen is the main symptom associated with PMP, which occurs because of conditions such as neoplasm, ascites, or renal abnormality. When the tumor gets larger, the abnormal growth results in the enlargement of either the entire abdomen or specific regions in the abdomen.

The surface of the peritoneum—a set of tissues that lines the abdominal wall and surrounds the inner organs of the abdomen—consists of a liquid called peritoneal fluid. This fluid helps in smooth movement of the tissues.

The amount of peritoneal fluid increases gradually as the tumor grows. This condition is known as ascites. It can also lead to increased abdominal girth. The increased liquid may then compress internal organs such as reproductive organs, digestive organs and organs of the urinary sytem, biliary system or gastrointestinal system. Abdominal pain may result from this. Inflammation of the large intestine is accompanied by redness, protrusion, and pain in the skin.



  • Hernia

A hernia occurs when a structure or part of an internal organ or tissue swells over a weak area such as a bone, a membrane, or a muscular tissue. It is mostly acquired in the abdomen and can be internal or external. Hernia is a commonly occurring condition and can affect any individual including women, men, and children.  


  • Constipation

Defecation difficulties or blockage that leads to swelling or pain in the abdomen is another symptom of pseudomyxoma peritonie.


  • Nausea and vomiting

Nausea and vomiting may be symptoms of many medical conditions. Both symptoms are related, but each one may occur separately. In PMP, these symptoms arise due to gastrointestinal disorders such as infectious gastroenteritis. It can also cause loss of appetite.


  • Respiratory insufficiency

Difficulty in breathing may occur due to the compression of internal organs, such as the lungs.

  • Loss of weight

Losing weight might be a symptom of many different types of disorders. However, in people affected by PMP it may occur gradual development of mucin inside the abdomen, which can lead to poor food intake. It results in the lack of proper nutrition.

  • Infertility

Infertility can arise because of many clinical conditions, PMP being one of them. If any unexplored symptoms arise, they must be verified by consulting a doctor.

Causes of PMP

The exact cause of PMP remains unknown. Hereditary, family, or ecological factors have not been associated with an increased risk this cancer. A number of dissimilar factors are involved in most of the cancers. A variety of tumors can lead to PMP. However, it is accepted that the site of origin of PMP is the appendix.

It is believed that the tumor cells from the affected appendix migrate to areas within the abdominal cavity and pelvis. The leaked tumor cells proceed to grow and produce mucinous ascites, which are dispersed throughout the abdomen.

Aggregation of mucin in the abdomen can lead to increased size of the latter. The profile of PMP is normally found by increasing the abdominal circumference and finally confirmed by the presence of mucus in the abdominal cavity (jelly belly).

Causes of PMP can be described using a number of theories.  From the patients’ medical records, specialists and researchers have identified other possible sites from where PMP can originate, which may include the urachas, stomach, colon, ovary, pancreas and other digestive system organs.

Risk factors

In retrospective studies, the most common attribute seen was age. It is likely to occur in the median age of 59 and above. A pre-existing neoplasm, either benign or malignant, in the appendix that is still alive and continues to develop in the abdomen, can cause PMP.

A benign tumor is non-cancerous because it grows in a specific region and does not spread easily, whereas malignant tumors are cancerous. People with a pre-existing neoplasm (malignant stage) are at a higher risk of negative outcomes.  

Further Reading

Last Updated: Jan 2, 2023


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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