Both benign and metastatic peritoneal mesothelioma are rare illnesses that occur when tumors develop in the abdomen lining. That said, metastatic peritoneal mesothelioma is much more common — and dangerous. Get a breakdown on both forms of peritoneal mesothelioma below.

Differences Between Metastatic and Benign Peritoneal Mesothelioma

The biggest difference between benign and metastatic peritoneal mesothelioma is that metastatic peritoneal mesothelioma is a form of cancer.

Metastatic peritoneal mesothelioma develops from malignant (cancerous) peritoneal mesothelioma. A patient will be diagnosed with metastatic peritoneal mesothelioma if cancerous tumors spread from the abdomen to other parts of the body.

The only known cause of metastatic peritoneal mesothelioma is asbestos exposure.

Some patients may be diagnosed with benign (non-cancerous) peritoneal mesothelioma. Benign peritoneal mesothelioma mainly affects women and is not linked to asbestos exposure.

Anyone who believes they are at risk of any type of mesothelioma should check in with their medical provider on a regular basis to stay safe.

Quick Answers About Benign Peritoneal Mesothelioma

Benign peritoneal mesothelioma is more rare and less deadly than metastatic peritoneal mesothelioma. Get answers to common questions about benign peritoneal mesothelioma below.

How many cases of benign peritoneal mesothelioma have been reported?

According to a 2019 study published in the Journal of Surgical Case Reports, there were fewer than 200 cases of benign multicystic peritoneal mesothelioma reported throughout the world in 2017.

Multicystic peritoneal mesothelioma means that there is more than one cyst (noncancerous growth) present.

What are the symptoms of benign peritoneal mesothelioma?

Benign peritoneal mesothelioma has very vague symptoms, and many are shared with metastatic peritoneal mesothelioma.

Benign peritoneal mesothelioma symptoms may include:

  • Abdominal fullness
  • Abdominal swelling
  • Changes in bowel habits
  • Chronic or occasional abdominal and/or pelvic pain
  • Intestinal obstruction
  • Unintentional weight gain

If you or a loved one is suffering from these symptoms, contact a medical professional immediately. Doctors can determine if the symptoms stem from benign or metastatic peritoneal mesothelioma.

Who is at risk of benign peritoneal mesothelioma?

83% of all benign peritoneal mesothelioma cases are found in women of reproductive age.

The condition can also affect males, but it is more rare. Asbestos exposure is actually not a risk factor for benign peritoneal mesothelioma.

What is the prognosis after a benign peritoneal mesothelioma diagnosis?

The prognosis for those diagnosed with benign peritoneal mesothelioma is very good, according to the 2019 study mentioned above.

The study did note that there were two reported cases of benign tumors becoming cancerous, with one death from the condition. That said, medical researchers believe that benign peritoneal mesothelioma only becomes cancerous in very rare cases.

Quick Answers About Metastatic Peritoneal Mesothelioma

Metastatic peritoneal mesothelioma has different symptoms and a different prognosis than benign peritoneal mesothelioma. Learn more about metastatic peritoneal mesothelioma below.

How many cases of metastatic peritoneal mesothelioma have been reported?

Malignant peritoneal mesothelioma is pretty rare, with about 300 new cases each year according to a 2017 American Cancer Society (ACS) report.

While metastasis to distant areas of the body may be rare as well, it is important for patients to know that malignant peritoneal mesothelioma can spread.

What are the symptoms of metastatic peritoneal mesothelioma?

Symptoms of metastatic peritoneal mesothelioma are often vague and can also vary from patient to patient. This can allow the tumor to spread throughout the abdomen without notice.

The most common symptoms of metastatic peritoneal mesothelioma include:

  • Abdominal swelling
  • Loss of appetite
  • Nausea
  • Nonspecific abdominal pain
  • Weight loss

In rare cases, patients may also experience fevers, night sweats, and a hernia.

Who is at risk of metastatic peritoneal mesothelioma?

Those exposed to asbestos are at risk of developing metastatic peritoneal mesothelioma. When inhaled or swallowed, asbestos fibers can get lodged in the body and eventually cause cancerous tumors to form.

Senior males are more likely to develop any type of malignant mesothelioma.

Since the cancer’s symptoms are mild, it becomes more likely that the diagnosis only takes place after it has spread to other sites in the abdomen.

What is the prognosis after a metastatic peritoneal mesothelioma diagnosis?

Metastatic peritoneal mesothelioma is usually fatal. Once the cancer spreads to other sites within the abdomen, it can become harder to safely treat.

Life expectancy is less than a year if the condition is not treated at all. However, treatment advances have been made that allow patients to extend their life expectancy.

Patients who do receive treatment have the best survival rates when compared to other forms of mesothelioma.

Treating Benign & Metastatic Peritoneal Mesothelioma

Both metastatic and benign mesothelioma are treated in similar manners despite the fact that one condition is cancerous while the other is not. The main treatment for both is called cytoreductive surgery with HIPEC.

Did You Know?

During cytoreductive surgery, the cancerous tumors are removed and a heated chemotherapy solution (HIPEC) is then applied to the surgery site.

Some patients with metastatic peritoneal mesothelioma may not qualify for this surgery if the cancer has spread throughout the body.

The biggest problem with both kinds of peritoneal mesothelioma is that they are extremely hard to diagnose. Most patients are not diagnosed until the tumors have started to spread.

An early diagnosis of peritoneal mesothelioma can help extend the lifespan. Since metastatic peritoneal mesothelioma is much more dangerous than benign peritoneal mesothelioma, it’s important to see a doctor immediately if symptoms develop.

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Laura WrightWritten by:

Lead Editor

Laura Wright is a journalist and content strategist with more than 15 years of professional experience. She attended college at the University of Florida, graduating magna cum laude with a bachelor’s degree in journalism in 2008. Her writing has been featured in The Gainesville Sun and other regional publications throughout Florida.

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  1. Kim, Joseph, et al. “Malignant Peritoneal Mesothelioma: a Review.” Annals of Translational Medicine, AME Publishing Company, June 2017,

  2. Sugarbaker, Paul H. “Cytoreductive Surgery and Intraperitoneal Chemotherapy for Treatment of Malignant Peritoneal Mesothelioma.” Caring for Patients with Mesothelioma: Principles and Guidelines, 2019, pp. 25–45., doi:10.1007/978-3-319-96244-3_3.

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