Peritoneal Mesothelioma

Peritoneal mesothelioma is the second most common form of mesothelioma. It affects the lining of the abdominal area, called the peritoneum.

Mesothelioma Vets - Peritoneal Mesothelioma

What is Peritoneal Mesothelioma?

Peritoneal mesothelioma occurs in the lining of the abdominal cavity. Between 20 to 30 percent of tumors develop in the peritoneum. Peritoneal mesothelioma patients tend to have a better prognosis compared to patients with pleural or pericardial mesothelioma.

Symptoms of Peritoneal Mesothelioma

Signs of peritoneal mesothelioma include abdominal pain and swelling, lumps in the abdomen, and unexplained weight loss. Patients may also develop abdominal fluid buildup, or ascites.

Other symptoms include:

  • Anemia
  • Body aches
  • Bowel obstruction
  • Constipation
  • Diarrhea
  • Fatigue
  • Fever or night sweats
  • Hernia
  • Nausea or vomiting

Peritoneal mesothelioma symptoms often mirror other illnesses, and is commonly misdiagnosed as:

  • Colorectal adenocarcinoma
  • Inguinal hernia
  • Irritable bowel syndrome (IBS)
  • Ovarian cancer
  • Primary peritoneal carcinoma
  • Stomach cancer

If you are experiencing these symptoms, visit your doctor immediately, and mention you may have been exposed to asbestos.

Causes of Peritoneal Mesothelioma

Similar to pleural or pericardial forms of the disease, asbestos exposure causes peritoneal mesothelioma.

Asbestos is a carcinogenic mineral used in commercial and residential buildings, and in the military. If disturbed, airborne asbestos fibers can be ingested, becoming trapped in the lining of the abdomen. Asbestos fibers buildup over a long period of time, causing inflammation and scarring. In an attempt to lubricate the area, the body creates an excess accumulation of fluid in the abdomen, called ascites. The buildup of ascites can result in cancerous cell mutations and the development of tumors.

Inhalation of airborne asbestos fibers may also lead to the development of peritoneal mesothelioma. The fibers can travel from the lungs to the abdomen through the lymphatic system, a part of the body’s immune system that fights off unwanted toxins.

Men are more likely to develop peritoneal mesothelioma than women. However, women can develop it through secondary exposure. Asbestos fibers can attach to clothing, skin, or hair, and indirectly expose family members, friends, and loved ones.

How Is Peritoneal Mesothelioma Diagnosed?

Mesothelioma has a long latency period — the time between asbestos exposure and when symptoms start to appear. It can take decades for the cancer to manifest. Once symptoms begin to appear, the disease has likely spread to other parts of the body.

The diagnostic process begins with a series of imaging tests such as X-rays, CAT scans, and MRIs. The imaging tests look for the presence of fluid in the abdomen. Doctors may take samples for fluid biopsies or run blood tests to detect any mutated mesothelial cells. Your doctor may also conduct a physical exam to check for any unusual signs, such as lumps or pain in the abdomen.

A tissue biopsy is the only definitive way to diagnose mesothelioma. Biopsies help determine what cell type is present in the tumor. Standard biopsies used for diagnosing peritoneal mesothelioma include:


Paracentesis is a type of needle biopsy used to obtain a sample of ascitic fluid from the abdomen. The procedure also removes excess fluid buildup, relieving pain or discomfort.


This biopsy uses a camera to help doctors view inside the patient’s abdomen. A peritoneoscopy identifies which organs may be affected. Doctors may also take a diagnostic sample of fluid or tissue during the procedure.


A laparotomy is a surgical procedure intended to remove as much of the tumor as possible. Doctors may perform a laparotomy for two reasons: to remove mesothelioma tumors, and collect a sample for further diagnostic investigation.

Stages of Peritoneal Mesothelioma

Doctors use the American Joint Committee on Cancer (AJCC) 1-4 staging scale to determine the stage for some peritoneal mesothelioma cases. Because the cancer is so rare, it doesn’t have its own formal staging system in place.

Doctors sometimes use a 1-3 staging scale based off past peritoneal mesothelioma timelines:

  • Stage 1: Tumors are localized in the abdominal cavity and have not spread to nearby lymph nodes. There is minimal cancerous tissue.
  • Stage 2: Tumors still haven’t spread to nearby lymph nodes, but the amount of cancerous tissue has increased.
  • Stage 3: Tumors have spread outside of the peritoneal lining and to nearby lymph nodes. The amount of cancer tissue is significant.

The Peritoneal Cancer Index (PCI) may also be used to assess the extent of the cancer and determine if it has spread to the lymph system. The PCI score ranges from 0-39, with a lower score indicating minimal tumors or spread and a better prognosis.

Treating Peritoneal Mesothelioma

Peritoneal mesothelioma is typically treated with a multimodal plan that includes chemotherapy, radiation, and if necessary, surgeons may attempt to remove the cancer during a procedure called a peritonectomy. The surgery can alleviate pain and discomfort and improve the patient’s quality of life.

The surgery is followed with heated chemotherapy to remove any remaining cancerous cells. The chemotherapy is applied directly to the infected area, reducing the negative impact of chemotherapy on other parts of the body. The survival time after patients receive the multimodal plan is between 52 and 92 months.

Additional treatments for peritoneal mesothelioma include clinical trials and immunotherapy.

Peritoneal Mesothelioma Prognosis

The prognosis, or projected course of the disease, is based off several factors:

  • Cell type
  • Genetic mutations
  • Location
  • Overall health
  • Sex: women tend to have a better prognosis than men
  • Stage at diagnosis
  • Treatments selected
  • Tumor grade (how fast it grows)

Patients with peritoneal mesothelioma tend to have a better prognosis than those with pleural or pericardial. Over time, advances in treatment have increased life expectancy and reduced pain.