Peritoneal mesothelioma is the second-most common form of mesothelioma, making up roughly 15-20% of cases. It develops in the peritoneum — the membrane lining the abdominal cavity and covering the abdominal organs.
Cause
Peritoneal mesothelioma is caused by asbestos exposure. It is thought to develop after asbestos fibers are swallowed, or after inhaled fibers migrate to the abdominal lining. Like other forms, it appears decades after exposure.
Symptoms
- Abdominal swelling and bloating (from fluid buildup, called ascites)
- Abdominal pain or cramping
- Changes in bowel habits
- Nausea and loss of appetite
- Unexplained weight loss
- A feeling of fullness
Because these symptoms mimic many common digestive conditions, peritoneal mesothelioma is often not suspected until it is advanced — again making an asbestos-exposure history critical to earlier diagnosis.
Diagnosis
Diagnosis involves imaging (CT, MRI), analysis of abdominal fluid, and a biopsy to confirm mesothelioma and its cell type.
Treatment
A leading treatment for eligible peritoneal patients is cytoreductive surgery combined with HIPEC (heated intraperitoneal chemotherapy) — surgery to remove visible tumor followed by heated chemotherapy delivered directly into the abdomen. Other treatments include systemic chemotherapy, immunotherapy, and clinical trials. Peritoneal mesothelioma treated with cytoreductive surgery plus HIPEC has, for some patients, shown notably better outcomes than historically expected — which is why evaluation at an experienced specialty center matters.
Symptoms That Point Elsewhere First
Abdominal mesothelioma presents as swelling, pain, bloating, changed bowel habit, loss of appetite and unexplained weight loss. Every one of those is more commonly caused by something benign, and the condition is frequently investigated for months as a gastrointestinal or gynaecological problem before anyone reaches for an asbestos history.
Fluid accumulating in the abdomen — ascites — is often the finding that prompts deeper investigation. As with pleural effusion, draining it relieves symptoms but does not treat the cause, and fluid analysis alone is frequently insufficient for diagnosis.
Why Peritoneal Disease Is Assessed Differently
Abdominal mesothelioma is not usefully described by the pleural stage numbers, and applying one to it can badly mislead. Surgeons instead use the Peritoneal Cancer Index (PCI), which divides the abdomen into thirteen regions, scores tumour bulk in each from 0 to 3, and sums them to a maximum of 39. The score predicts whether cytoreductive surgery is feasible and how complete the removal is likely to be.
Cytoreductive Surgery with HIPEC
The treatment that changed outcomes for this form combines two steps in one operation. Cytoreductive surgery (CRS) removes visible tumour from the peritoneal surfaces and affected organs. Heated intraperitoneal chemotherapy (HIPEC) then circulates warmed chemotherapy directly through the abdominal cavity for a set period, reaching microscopic disease the surgeon cannot see at concentrations systemic chemotherapy could not safely deliver.
Published series report median survival measured in years rather than months for carefully selected patients — the longest outcomes reported in any mesothelioma group. Selection is the operative word: it depends on PCI score, cell type, overall fitness, and whether a complete or near-complete cytoreduction looks achievable.
This is a long, demanding operation performed at a limited number of centres. A peritoneal diagnosis is worth taking to a surgeon who does it regularly, and a prognosis quoted from pleural statistics should not be used to set expectations for it.
Prognosis
Prognosis varies by cell type, extent of disease, and treatment. See the life expectancy and prognosis guide for more.
If you were diagnosed with peritoneal mesothelioma and were exposed to asbestos at work, in the military, or in a building, you may have a legal claim.
This information is educational, drawn from sources such as the American Cancer Society and National Cancer Institute, and is not medical advice. Consult your own physician about diagnosis and treatment.