Pseudomyxoma Peritonei

What is pseudomyxoma peritonei (PMP)?

Pseudomyxoma peritonei (SOO-doh-mix-OH-muh PAYR-ih-TOH-nee-EYE) is a rare type of cancer that affects your peritoneal cavity (your abdomen and pelvis). The name literally means “false mucinous tumor of the peritoneum.” It’s called a false tumor because this cancer doesn’t actually grow into solid tumors. Instead, it spreads by continuously producing mucin, a jelly-like substance that is one of the components of mucus. The mucin gradually accumulates in your peritoneal cavity, which is what has given this condition the nickname, “jelly belly.”

The cancer begins as a polyp, usually on the inside lining of your appendix. Some research suggests it could also begin in other organs, but this would be very rare. The cancer cells secrete mucin until the appendix swells and bursts, allowing the mucin to spread throughout your peritoneal cavity.

PMP doesn’t spread through your blood or lymphatic system like other cancers, but it can spread to the surface of many of your abdominopelvic organs. This makes it difficult to treat. To cure PMP, you usually have to remove all of the affected tissue, including organs.

How common is this condition?

Pseudomyxoma peritonei is very rare. It affects around 2 people per 1 million each year.

What causes PMP?

Like many cancers, pseudomyxoma peritonei develops for unknown reasons. It doesn’t appear to be affected by genes or environmental factors.

What are the signs and symptoms of pseudomyxoma peritonei?

In the early stages, you likely won’t notice any symptoms. This is why PMP often isn’t discovered until it has had time to advance.

PMP advances slowly over many years. If you have symptoms at all, it is likely to be from the accumulation of mucin in your belly. The mucin spreads through the inside lining of the peritoneal cavity, called the peritoneum. This leads to ascites, an increase in the fluid that lubricates the peritoneum. Mucinous ascites causes swelling and eventually begins to compress your organs. This can cause problems in your digestion and reproductive systems.

You may notice symptoms such as:

• Bloated stomach. Mucinous ascites cause your abdomen to swell. You may notice a gradual increase in your waist size or your weight that can’t be explained by other causes.
• Abdominal pain. You may feel general discomfort, pressure or inflammation inside your peritoneum, or in one of your organs if it is particularly affected.
• Indigestion. Compression in your digestive system may cause nausea or loss of appetite.
• Constipation. Abdominal swelling may cause an intestinal blockage.
• Hernias. Compression may push one of your organs through a gap in your muscle wall. Inguinal hernia is one of the most common findings in people assigned male at birth.
• Difficulty getting pregnant. Compression or inflammation in your reproductive organs can make it difficult to conceive, especially for people assigned female at birth.

How is pseudomyxoma peritonei diagnosed?

Because symptoms tend to be mild, vague and late-occurring, PMP can be tricky to diagnose. In the best cases, it’s discovered by accident during a routine checkup or while looking for something else. This can give you and your healthcare provider a head start in watching it and treating it. However, most people come to their healthcare providers with abdominal symptoms. When this happens, your healthcare provider will begin by physically examining you and follow up with imaging tests (radiology). This may mean an ultrasound, CT scan or MRI.

Imaging may show ascites, enlarged organs, or “jelly belly” — characteristic mucin deposits in your abdomen. But if imaging isn’t enough to diagnose PMP, your healthcare provider may turn to cytology — analyzing a sample of fluid or tissue from your abdomen. They may use a needle to draw fluid from your peritoneum or take a tissue sample to examine (needle biopsy). They may examine the inside of your abdomen through a laparoscopy, a procedure that places a tiny camera through a tiny incision. They can also take tissue samples through the incision.

PMP may be mistaken at first for other, more common conditions, including:

• Ovarian cancer.
• Mesothelioma.
• Appendicitis.

How is pseudomyxoma peritonei treated?

Treatment will depend on your condition. The best chance of curing PMP is to remove all of the affected tissue and follow with chemotherapy in your abdomen (intraperitoneal). However, this requires extensive surgery and a strong immune system, and it may not be safe for everyone. If your healthcare provider can’t remove all of the cancer, they will try to remove as much as possible and manage the symptoms and side effects of the condition. This will mean regular testing and possibly repeat treatments as the cancer reappears or grows.

The treatment options include:

• The Sugarbaker technique: cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC).
• Debulking surgery.
• Nonsurgical treatment.

The Sugarbaker technique

This is the gold standard treatment for pseudomyxoma peritonei, and it can be curative. But it's very intensive and comes with its own set of risks. The treatment is nicknamed the “Sugarbaker” after Dr. Paul Sugarbaker, who first developed it. It involves extensive open abdominal surgery to remove the affected tissues. This is called “cytoreduction”, which means “reducing the number of cells” (cancer cells). At the end of the surgery, an infusion of heated chemotherapy helps to kill any stray cancer cells that may have been left behind.

Surgery may include:

• Peritonectomy. Removal of the peritoneum, the lining of your abdominal and pelvic cavities.
• Omentectomy. Removal of the adipose tissue (fat layer) that covers the front of your abdomen.
• Bowel resection. Removal of the small or large intestine. Sometimes this will also require an ostomy, which may be permanent or temporary.
• Splenectomy. Removal of your spleen. Your spleen is part of your immune system. After removing it, you’ll have to take antibiotics for the rest of your life to help prevent infections.
• Cholecystectomy. Removal of your gallbladder. You won’t notice this one so much afterward.
• Liver capsulectomy. A partial resection of the surface of the liver where mucin tends to accumulate. Your liver can regenerate after you remove a piece.
• Hysterectomy with bilateral salpingo-oophorectomy. Removal of your uterus and ovaries.

The surgery itself can take between 10 to 14 hours. After all the visible cancer has been removed, the operation finishes with a dose of chemotherapy — specifically, hyperthermic intraperitoneal chemotherapy (HIPEC). This means your surgeon will fill your peritoneal cavity with a heated liquid formula of cancer-killing drugs (usually mitomycin C). Heating the formula to 42 degrees helps the tissues absorb it better. After about 60 to 90 minutes, your surgeon will drain the liquid, close your incisions and complete the operation.

The object of the Sugarbaker operation is to remove all of the cancer for good. Most of the time, it works, but sometimes, more treatment is needed. In some cases, the tumor can grow back and the treatment may be repeated. On the other hand, sometimes your surgeon knows in advance that they won’t be able to take out all of the affected tissue. There may be various reasons why you can’t have all of those parts removed at once, or you can’t be in surgery for that long. When this is the case, they’ll recommend debulking surgery.

Debulking surgery

The purpose of debulking is to remove as much cancer as possible, within the limits of your particular condition. Sometimes debulking surgery is also called cytoreductive surgery, which can be confusing. Technically, it is intended to reduce the cancer cells in your body, just like the Sugarbaker. The only difference is that it isn’t expected to be completely cytoreductive. Debulking can help remove mucin and reduce symptoms, such as abdominal bloating and pressure on your organs. But when these return, you will most likely need more surgery.

Sometimes debulking surgery is a first step in managing your condition that puts you in a better state for future treatment. You may be able to follow debulking surgery with complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) sometime later. In other cases, your surgeon may know that they won’t be able to remove it all. Instead, they'll continue to keep you under close observation for the rest of your life. They may recommend a permanent colostomy to protect your intestines from becoming blocked by the mucin.

Nonsurgical treatment

If surgery is not a safe option for you, your options are:

• Watch and wait. If you have early or slow-growing PMP and the risks of surgery outweigh the current risks of the disease, your healthcare provider may decide to wait and monitor your condition until the circumstances change. You’ll have regular blood tests to check for cancer markers.
• Palliative care. If your PMP is advancing but you still aren’t a candidate for surgery, your healthcare provider will attempt to slow it down and relieve your symptoms through palliative care. This may include radiation therapy, systemic chemotherapy or other drug therapies.

What are the complications or side effects of the treatment?

Complications of cytoreductive surgery include:

• Paralytic ileus. Your bowels may not want to move following surgery.
• Peripheral neuropathy. Damage to a nerve, causing tingling or numbness in the area.
• Blood clots. The risk is higher due to the long time on the operating table.
• Anastomotic leak. Two parts of a channel sewn together can leak.
• Septicemia and sepsis. The peritoneal fluid can become infected, and the infection can spread to your systemic bloodstream.
• Pleural effusion. A buildup of fluid in the tissue surrounding your lungs.

Complications of chemotherapy include:

• Neutropenia. Low levels of immune cells, leaving you more vulnerable to infection.
• Mucositis. Inflammation of the mucous lining of your gastrointestinal tract.
• Nausea and vomiting. This is temporary, but it can lead to poor appetite and undernutrition.
• Fatigue. It will take some time to feel like yourself after treatment.

Is pseudomyxoma peritonei curable?

Yes. If all of the cancer cells are removed from the peritoneal cavity, it is possible to be cured. While the treatment for PMP is challenging, the ability to locate the cancer in a limited area makes it more possible to conquer than some other cancers. It doesn’t become systemic throughout your body.

If it isn’t cured, you can still live a long time with pseudomyxoma peritonei. Palliative care can help you manage symptoms and slow down the progression of PMP. However, you will be visiting your healthcare provider regularly for testing and treatment for the rest of your life.

A note from Cleveland Clinic

Pseudomyxoma peritonei is not something anyone expects. It appears to strike randomly, for no known reason and can live and grow for a long time without causing any symptoms. When symptoms do arrive, they come from the bizarre phenomenon of "jelly belly." This is not the version of cancer we are familiar with from popular culture. And what it means for you can be a lot to process. On one hand, treating PMP may involve sacrificing multiple organs from your digestive and reproductive systems. But on the other hand, doing this can cure you.