Peritoneal mesothelioma is cancer of the peritoneum, the thin lining that covers the organs and inner walls of the abdomen. It is the second most common form of mesothelioma: the American Cancer Society reports that pleural cases make up roughly 3 out of 4 mesotheliomas and peritoneal cases account for most of the rest. Like the pleural form, it is caused by asbestos exposure, per the National Cancer Institute.
This page is informational, not medical advice. Testing and treatment decisions belong with your care team.
What are the symptoms of peritoneal mesothelioma?
Per the American Cancer Society, the common signs are abdominal pain, swelling of the belly, fluid buildup in the abdomen (called ascites), nausea and vomiting, constipation, and unexplained weight loss. None of these points to a rare cancer on its face. They look like gallbladder disease, hernia, ovarian trouble, or ordinary digestive problems, and peritoneal mesothelioma is often investigated for some time under those headings before the real answer surfaces. If these symptoms persist in someone with any asbestos history, that history belongs in the conversation with the doctor.
How does asbestos reach the abdomen?
Asbestos fibers enter the body by being inhaled or swallowed, and the NCI fact sheet documents that trapped fibers can cause disease in the lining of the abdomen as well as the chest. The exposure sources are the same ones behind every asbestos disease: industrial and trade work, and household exposure from fibers carried home on work clothes, which the NCI also documents. The same 20-to-50-year latency applies, so the exposure behind a diagnosis today usually traces to jobs held decades ago. Our asbestos exposure guide covers where those exposures happened in Pennsylvania.
How is peritoneal mesothelioma diagnosed?
The path mirrors the pleural workup: imaging first, then fluid, then tissue. Per the ACS, doctors may drain abdominal fluid with a needle (paracentesis) and test it, but a biopsy, often taken through a camera-guided procedure called laparoscopy, is what confirms the disease. Unlike pleural mesothelioma, the peritoneal form has no established formal staging system; the ACS staging guide notes the formal system applies to pleural disease, so doctors describe the extent of peritoneal disease from imaging and surgical findings instead.
How is it treated?
The ACS surgery guide describes the approach used for selected peritoneal patients: surgery to remove as much tumor as possible from the abdomen, often combined with heated chemotherapy circulated through the abdominal cavity during the operation. Chemotherapy given by vein is also used, and the National Cancer Institute’s treatment summary (NCI PDQ) covers the full set of treatment categories for mesothelioma. Whether the surgical approach fits a particular person depends on the extent of disease and overall health, and that judgment belongs to the treating team. Our treatment overview explains each category in plain terms.
What does prognosis look like for this form?
Survival statistics for mesothelioma are usually reported for the pleural form, where the patient numbers are largest and the research is deepest: the American Cancer Society reports a five-year relative survival rate of about 12 percent for pleural mesothelioma across all stages. Those figures are group averages built from patients diagnosed years ago, and the ACS is explicit that they cannot predict what will happen to any individual. They also do not map cleanly onto the peritoneal form, which is treated differently and behaves differently. The honest answer for a peritoneal patient is that the outlook depends on how much disease is present, whether surgery is possible, the cell type, and overall health, and the treating oncologist is the only person with those facts in hand. Our prognosis page explains what survival statistics can and cannot tell one family.
How is the peritoneal form different from the pleural form?
Different location, different symptoms, different treatment planning, same cause. Both are mesothelioma, both are confirmed by biopsy, and both are compensable. The pleural form is covered on our pleural mesothelioma page, and the full disease cluster is mapped on the asbestos diseases hub. One practical note for families: because the peritoneal form is the rarer of the two, second opinions from a major cancer center are common and worth asking about.
What this means for your family
Legally, a peritoneal mesothelioma diagnosis stands on the same footing as a pleural one. It generally opens Pennsylvania’s two-year filing window (42 Pa. C.S. § 5524), it qualifies for claims against the companies responsible for the exposure, and it qualifies under asbestos bankruptcy trust funds, which hold roughly $30 billion set aside for asbestos victims per the U.S. Government Accountability Office (GAO-11-819). The winding diagnostic road many peritoneal patients travel does not weaken the claim; the clock runs from discovery of the disease, not from the first misread symptom.
If peritoneal mesothelioma has been diagnosed in your family, request a free case review and get clear answers about the deadline and the path forward.