Peritoneal Mesothelioma

Peritoneal mesothelioma is a type of cancer that is caused by ingested asbestos fibers. It develops in the peritoneum, the thin layer of tissue lining the abdomen. Symptoms of peritoneal mesothelioma include abdominal pain, nausea, and swelling in the abdomen (ascites).

What Is Peritoneal Mesothelioma?

Peritoneal mesothelioma is a rare asbestos-related cancer that forms on the abdominal lining, known as the peritoneum. An even rarer form of this cancer develops in a layer of the abdominal membrane, the omentum, that covers the stomach and other organs.

  • Early symptoms include abdominal swelling and fluid buildup (known as ascites).
  • Peritoneal mesothelioma accounts for less than 20% of all mesothelioma cases.
  • Surgery with heated chemotherapy is the most effective treatment, helping some patients survive for more than five years.

The primary cause of peritoneal mesothelioma is swallowing airborne asbestos fibers or drinking contaminated water. The digested fibers become trapped in the peritoneum.

What Are the Symptoms of Peritoneal Mesothelioma Cancer?

Early symptoms of peritoneal mesothelioma include bloating, pain or tenderness around the abdomen, and digestion issues such as constipation or diarrhea.


  • Abdominal pain
  • Abdominal swelling (ascites)
  • Night sweats
  • Nausea
  • Fever
  • Unexplained weight loss
  • Fatigue
  • Diarrhea
  • Constipation
  • Loss of appetite

These symptoms tend to mimic many other abdominal disorders. An accurate diagnosis often requires a mesothelioma specialist and a biopsy sample. 

Anyone with a history of asbestos exposure should monitor their health and see their doctor for new or worsening symptoms.

What Causes Peritoneal Mesothelioma?

The main cause of malignant peritoneal mesothelioma is ingesting asbestos fibers. Current research suggests that asbestos fibers travel from the digestive tract and remain trapped in the abdomen, causing cancer after years of inflammation.

Process of Peritoneal Mesothelioma Development

Like other asbestos-related diseases, peritoneal mesothelioma develops over a long period of time. The trapped asbestos fibers cause inflammation and irritation, damaging and degrading DNA. 

Damaged DNA can lead to abnormal and unregulated cell growth. These errors cause tumors to form, and the tumors can grow uncontrollably and spread to other areas of the body. HOW PERITONEAL MESOTHELIOMA DEVELOPS

  • Swallowed asbestos fibers pass through the stomach and digestive system.
  • Ingested asbestos fibers reach the lymphatic system and travel to the peritoneum.
  • Fibers become stuck in the peritoneum, irritating cells and damaging DNA for years.
  • The irritated cells become inflamed, form scar tissue and thicken the peritoneal lining.
  • Years of inflammation and scar tissue formation cause excess abdominal fluid buildup.
  • After prolonged damage, malignant tumors begin to form on the diseased peritoneum.
  • As tumors grow, they put pressure on vital organs and can spread to form new tumors.

Research on peritoneal mesothelioma is still ongoing. Other sources of this disease may include abdominal radiation and fibrous minerals besides asbestos, such as erionite.

How Is Peritoneal Mesothelioma Diagnosed?

Imaging scans, blood tests, and biopsies are used to make an abdominal mesothelioma diagnosis.

  • Imaging scans show the size and location of tumors.
  • Blood tests reveal certain biomarkers associated with cancer.
  • Biopsies show what kind of cancerous cells are present.

Patients will also receive a thorough examination of their medical history, occupational history, and overall physical condition.

While every test serves a contributing purpose to the diagnostic process, the only way to confirm a peritoneal mesothelioma diagnosis is with a biopsy.

Biopsies are samples of tumor tissue that doctors examine under a microscope in a lab. Medical professionals, called pathologists, perform tests on the biopsy sample to reveal the kinds of cancerous cells within the tumors. They then summarize the results in a pathology report.

Diagnosing Cell Types of Peritoneal Mesothelioma

The pathology report contains information about which cellular subtype of peritoneal mesothelioma you have.

Common Cell Types

  • Epithelioid cells: are the most common, making up 75% of cases.
  • Biphasic Cells: Second-most common type, making up 25% of cases. A mix of epithelioid and sarcomatoid cells.

Epithelioid peritoneal mesothelioma can grow in four different patterns: Papillary, tubular, diffuse, and deciduous. Papillary is the most common and often appears alongside the others.

Pure sarcomatoid tumors are uncommon in peritoneal mesothelioma. Specialists have only diagnosed about 30 cases of this variant since 2006. Sarcomatoid cells usually occur alongside epithelioid cells to form the biphasic subtype.

Rare Cell Types

  • Well-Differentiated Papillary Mesothelioma: This variant is uncommon with less potential for malignancy and typically presents in younger women.
  • Multicystic Mesothelioma: This subtype often recurs after surgery and does not have a definitive link with asbestos exposure.
  • Desmoplastic Mesothelioma: This tumor type can present as nodules or a mass-like peritoneal thickening, ascites or lymph node disease.
  • Lymphohistiocytoid Mesothelioma: A dense lymphatic infiltrate characterizes this variant.
  • Pure Sarcomatoid Mesothelioma: The rarest and most lethal form of peritoneal mesothelioma, this subtype is associated with aggressive metastasis.

Additionally, omental mesothelioma is a rare variant in the omentum, a part of the peritoneum surrounding the stomach and other abdominal organs. The omentum is a layer of fatty tissue that plays a role in immune function and metabolism. DID YOU KNOW? The Mesothelioma Center at has helped more than 1,000 patients diagnosed with peritoneal mesothelioma since 2017.


Because this cancer is rare, doctors lacking experience with the disease often misdiagnose abdominal mesothelioma patients with more common illnesses that share similar symptoms. Peritoneal mesothelioma misdiagnosis can delay proper treatment.

If you have a history of asbestos exposure, the best way to ensure an accurate diagnosis is to schedule an appointment with a mesothelioma specialist. Doctors who specialize in peritoneal mesothelioma have the knowledge and tools needed to make a precise diagnosis.