Written By: Devin Golden

Peritoneal Thickening

Peritoneal thickening is scar tissue in the peritoneum, possibly due to asbestos exposure. The peritoneum is the thin lining inside the abdominal cavity and where peritoneal mesothelioma cancer forms. Peritoneal thickening is one of the symptoms of peritoneal mesothelioma.

Karen Ritter, RN BSN

Medically Reviewed By

Karen Ritter, RN BSN

Registered Nurse

Karen Ritter, RN BSN

Medically Reviewed By

Karen Ritter, RN BSN

Registered Nurse


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Brief Explanation of Peritoneal Thickening

Peritoneal thickening is the buildup of scar tissue in the peritoneum, which is within the peritoneal cavity. This condition is a disease in the peritoneal cavity. This is a thin lining around the abdominal cavity and all of its organs, including the small and large intestines, pancreas, bladder, stomach, spleen, and liver. The peritoneum is made up of two thin layers of tissue and a space in between with peritoneal fluid. These two layers are the:

  • Parietal peritoneum – Outer layer attached to the abdominal and pelvic walls
  • Visceral peritoneum – Inner layer covers the organs in the abdominal cavity

Peritoneal thickening can be malignant (cancerous) or benign (noncancerous). A malignancy is more serious than benign thickening.

Types of Thickening

Aside from being either benign or cancerous, there are three types of thickening of the peritoneum. These types can indicate whether the scar tissue is associated with cancer or another condition:

  • Smooth peritoneal thickening – Continuous, regular and uniform thickening
  • Irregular peritoneal thickening – Continuous, nonuniform thickening with some areas thicker than others
  • Nodular peritoneal thickening – Separate nodules of thickening

Smooth peritoneal thickening is often a sign of peritonitis, which is an inflammation of the peritoneum. Irregular peritoneal thickening is the type most often associated with peritoneal mesothelioma cancer. Nodular peritoneal thickening is a sign of peritoneal carcinomatosis and peritoneal lymphomatosis.

Peritoneal Thickening and Peritoneal Mesothelioma

Peritoneal mesothelioma cancer starts in the peritoneum and forms from mesothelial cells in the lining. This cancer is diagnosed in fewer than 1,000 people in the U.S. each year.

When tumors form, they can lead to scar tissue developing in the peritoneum. The only cause of peritoneal mesothelioma is asbestos exposure. If your peritoneal thickening is a symptom of this type of cancer, then it’s caused by sharp asbestos fibers irritating the peritoneal tissue linings.

Peritoneal thickening does not occur substantially in all cases of peritoneal mesothelioma. In one study, 44% of diffuse malignant peritoneal mesothelioma cases showed irregular or massive thickening.

Peritoneal Thickening and Other Conditions

Thickening can be a sign of numerous other peritoneal diseases. These include:

  • Peritonitis
  • Peritoneal carcinomatosis
  • Peritoneal tuberculosis
  • A cancer of the abdominal cavity that spreads to the peritoneum (peritoneal metastasis, or secondary peritoneal cancer)

Peritoneal mesothelioma and peritoneal carcinomatosis are considered primary peritoneal cancers.

Peritoneal Plaques and Peritoneal Thickening

Peritoneal plaques are deposits of collagen fibers, also called scar tissue, in the lining of the abdominal cavity. These deposits collect in the peritoneum and are a sign of peritoneal mesothelioma.

Peritoneal plaques are rare and much less common than pleural plaques (scar tissue buildup in the lining of the lungs).

Peritoneal Thickening Causes

Exposure to asbestos is one of the main causes of peritoneal wall thickening. This link occurs when peritoneal thickening is a symptom of peritoneal mesothelioma.

Another condition linked to peritoneal thickening is peritonitis, which is an infection within the peritoneum. Peritoneal thickening from peritonitis occurs when bacteria enter the peritoneum through a perforation (hole) in your gastrointestinal tract. This can occur due to a hole in your colon or a ruptured appendix.

Another cause of peritoneal thickening is abdominal cancer that metastasizes (spreads) to the peritoneum. An example is ovarian cancer or liver cancer that spreads to the peritoneum.

How to Diagnose Peritoneal Thickening

The most common ways to diagnose malignant and diffuse peritoneal thickening are with an abdominal X-ray or a CT scan. CT scans show the entire peritoneum in detail, which can reveal the severity of peritoneal thickening. CT scans can also reveal peritoneal plaques, if they exist.

Other tests for peritoneal thickening include an MRI scan and a PET scan.

Peritoneal Thickening Symptoms

Peritoneal thickening symptoms are similar to the main symptoms of peritoneal mesothelioma. Some of these symptoms are nonspecific and can be caused by a number of conditions related to the abdominal cavity:

  • Abdominal pain
  • Ascites (fluid buildup in the peritoneum)
  • Distension (swelling of the abdomen)
  • Fever
  • Weight loss

Peritoneal Thickening Treatment

If you’re wondering, “How is peritoneal thickening treated?”, there is not any specific treatment for this condition. There are treatments for conditions that cause peritoneal thickening, but the scar tissue in the peritoneum is irreversible.

Malignant mesothelioma treatment involves chemotherapy, surgery and fluid drainage. Surgery for this cancer is cytoreduction with heated intraperitoneal chemotherapy. Cytoreduction often involves removing the peritoneum, which is called a peritonectomy. Removing the peritoneum will remove the peritoneal thickening and relieve symptoms.

Peritonitis treatment usually involves antibiotics to address infections caused by bacteria. Some people with peritonitis require surgery since it’s a deadly infection that can spread through the body if not treated. Surgery for peritonitis involves removing the infected tissue from the peritoneal cavity.

Peritoneal Thickening Life Expectancy

Life expectancy with peritoneal thickening depends on the cause of the condition. For instance, if the thickening is due to primary peritoneal cancer (such as peritoneal mesothelioma), then the life expectancy is 1-2 years. However, surgery for peritoneal mesothelioma has led to average survival times of 4-5 years at some top cancer centers.

If the thickening is due to secondary peritoneal cancer (metastasis into the peritoneum from stomach cancer, colon cancer, pancreatic cancer or another cancer), then the life expectancy is shorter. According to one study, secondary peritoneal cancers have a life expectancy of around six months.

If the thickening is due to peritonitis, then the life expectancy has a wide range. Peritonitis is a bacterial infection, and it can be deadly but usually can be controlled with treatment. According to a study in the World Journal of Hepatology, the mortality rate ranges from 20%-40%.

Frequently Asked Questions About Peritoneal Thickening

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Does Peritoneal Thickening Mean Cancer?

Peritoneal thickening is not always a symptom of cancer. It is a symptom of peritoneal mesothelioma, a rare cancer, and a symptom of peritoneal carcinomatosis, but it can also be a symptom of noncancerous conditions such as peritoneal tuberculosis and peritonitis. The only definitive way to tell if your peritoneal thickening is due to cancer is by undergoing imaging tests, blood tests, and possibly a biopsy with tissue examination under a microscope.

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Can Peritoneal Thickening Be Cured?

Peritoneal thickening is scar tissue and tissue inflammation inside of the peritoneum. This scar tissue cannot be cured. There are treatment options, such as palliative surgeries to reduce symptoms and discomfort. Cytoreductive surgery is the main peritoneal mesothelioma surgery and may include a peritonectomy, which will remove the peritoneum and the scar tissue within it. However, the buildup of scar tissue is irreversible.

Sources & Author

  1. Malignant peritoneal mesothelioma: a review. Annals of Translational Medicine. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5497105/. Accessed: 03/16/2023.
  2. Peritoneal thickening. Radiopaedia.org. Retrieved from: https://radiopaedia.org/articles/peritoneal-thickening. Accessed: 03/23/2023.
  3. Computed Tomographic Features of Malignant Peritoneal Mesothelioma. Anticancer Research. Retrieved from: https://ar.iiarjournals.org/content/36/3/1067. Accessed: 03/23/2023.
Devin Golden

About the Writer, Devin Golden

Devin Golden is a content writer for Mesothelioma Guide. He produces mesothelioma-related content on various mediums, including the Mesothelioma Guide website and social media channels. Devin's objective is to translate complex information regarding mesothelioma into informative, easily absorbable content to help patients and their loved ones.