Pseudomyxoma peritonei has three typical characteristics! Are there any early warning signs?

Author: Li Yan, Chief Physician of Beijing Tsinghua Chang Gung Hospital affiliated to Tsinghua University

Reviewer: Ge Yuping, deputy chief physician, Peking Union Medical College Hospital

The peritoneum is a layer of membranous tissue that covers most of the organs in the abdominal cavity. It can secrete mucus to moisten the surface of the organs and reduce friction between the organs.

Figure 1 Original copyright image, no permission to reprint

Tumors can also occur in the peritoneum, which are divided into primary peritoneal tumors and secondary peritoneal tumors. Primary peritoneal tumors are relatively rare, mainly including pseudomyxoma peritonei and mesothelioma, while secondary peritoneal tumors are metastatic tumors.

Today we will learn about pseudomyxoma peritonei.

1. What is pseudomyxoma peritonei?

The normal human body contains a variety of mucus cells, which are distributed in the gastrointestinal tract, uterus, ovaries, etc. These mucus cells usually secrete mucus to keep the related tissues lubricated.

When mucous cells become cancerous, tumor cells will be widely implanted in the peritoneum or omentum (including the greater omentum, lesser omentum, and the peritoneum covering the gastrointestinal tract, uterus and ovaries) and secrete a large amount of mucus, resulting in a large amount of gelatinous, mucinous ascites in the abdominal cavity, forming the so-called gelatinous abdominal cavity, called pseudomyxoma peritonei.

The reason why it contains the word "false" is because it is essentially a secondary peritoneal tumor caused by the implantation of tumor cells in the peritoneum.

Pseudomyxoma peritonei is a malignant tumor in terms of biological properties and has several typical characteristics. First, it grows uncontrollably. Currently, there is no drug or treatment that can control its growth, and it is not regulated by the body's growth factors. Second, it is invasive and will invade the gastrointestinal tract, liver, and other organs, thereby destroying them. Third, it can cause severe clinical symptoms, such as obvious abdominal distension, significant increase in ascites, and the formation of a large abdominal mass, which can easily lead to intestinal obstruction.

2. What is the cause of pseudomyxoma peritonei?

The formation of pseudomyxoma peritonei and other malignant tumors are basically similar in terms of disease principles. First, normal cells in the human body mutate. Pseudomyxoma peritonei is caused by the malignant transformation of mucus cells.

The most basic theory about the formation of pseudomyxoma peritonei is cell mutation, but its exact cause is still unclear. However, it is known that there are some high-risk factors, such as overactive mucus cell secretion and people with particularly obese constitutions are more likely to develop the disease. In addition, people with a history of chronic diseases, such as appendicitis, abdominal abscesses, or chronic abdominal inflammation, are also considered to be one of the factors that induce the disease.

3. Are there any early symptoms of pseudomyxoma peritonei?

There are several good early warning signs of pseudomyxoma peritonei.

First, if you have symptoms similar to appendicitis that are inexplicably present, especially for people over middle age, if you have recurrent right lower abdominal pain, and the pain persists and recurs repeatedly, you should rule out appendicitis. This vague right lower abdominal pain may be an early sign of pseudomyxoma peritonei.

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Second, some patients will notice that the left and right sides of their abdomen are asymmetrical, and the right side usually feels harder or larger than the left side. This is also one of the early warning signs of pseudomyxoma peritonei.

4. What examinations are needed to diagnose pseudomyxoma peritonei?

When warning signs appear and pseudomyxoma peritonei is suspected, the next step is to examine with specialized instruments. The preferred examination method is B-ultrasound, which can clearly show whether there is ascites in the abdominal cavity, pelvic cavity or abdominopelvic cavity, as well as the amount and nature of ascites, and distinguish whether it is clear or viscous ascites.

A more professional examination method is to perform a full abdominal and pelvic CT scan, which can fully understand the distribution of ascites in the abdominal cavity, from top to bottom, from front to back, and from left to right. In addition, CT can also evaluate whether ascites or tumors have caused significant compression to organs such as the liver, gastrointestinal tract, spleen, uterus, and ovaries.

Another important examination is the iodine water contrast examination, which can record the movement of the gastrointestinal tract in real time. By analyzing the movement trajectory of the gastrointestinal tract, the impact of the tumor on the gastrointestinal tract and its mesentery can be determined.

These are all very critical imaging examination methods. In addition, laboratory tests are also very important. The diagnosis of pseudomyxoma peritonei usually involves three important tumor markers: CEA (carcinoembryonic antigen), CA199 (carbohydrate antigen 199) and CA125 (carbohydrate antigen 125). These indicators are crucial for judging the proliferation, invasion and destructive power of the tumor.

The final diagnosis is usually achieved through imaging-guided abdominal puncture and pathological examination.