Primary malignant peritoneal tumor

Primary malignant peritoneal tumor refers to a group of rare cancers that originate directly in the peritoneum — the thin membrane lining the abdominal cavity and covering the abdominal organs. Unlike secondary peritoneal cancers that spread (metastasize) from other organs such as the ovaries, colon, or stomach, these tumors arise de novo within the peritoneal tissue itself. The most well-known subtype is primary peritoneal carcinoma, which closely resembles high-grade serous ovarian cancer both histologically and clinically, but other subtypes include malignant peritoneal mesothelioma and primary peritoneal serous carcinoma. Patients may present with abdominal distension, ascites (fluid accumulation in the abdomen), abdominal or pelvic pain, bloating, changes in bowel habits, weight loss, and fatigue. Because symptoms are often nonspecific, diagnosis is frequently delayed until the disease is at an advanced stage. The peritoneum and abdominal organs are the primary body systems affected. Tumor spread across the peritoneal surfaces can impair the function of the intestines, liver surface, diaphragm, and other intra-abdominal structures. Diagnosis typically involves imaging (CT or MRI), measurement of tumor markers such as CA-125, and definitive histopathological confirmation through biopsy or surgical specimens. Treatment generally follows protocols similar to those used for advanced ovarian cancer and may include cytoreductive surgery (CRS) aimed at removing all visible tumor, combined with hyperthermic intraperitoneal chemotherapy (HIPEC) or systemic platinum-based chemotherapy. Targeted therapies and PARP inhibitors may also be considered depending on the molecular profile of the tumor. Prognosis varies depending on the histological subtype, extent of disease, and response to treatment, but outcomes have improved with advances in surgical techniques and chemotherapy regimens.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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