Primary peritoneal cancer or carcinoma is also known as serous surface papillary carcinoma, primary peritoneal carcinoma, extra-ovarian serous carcinoma, primary serous papillary carcinoma, psammomacarcinoma. It was historically classified under "carcinoma of unknown primary" (CUP). Primary peritoneal cancer (PPC, or PPCa) is a cancer of the cells lining the peritoneum, or abdominal cavity.
Prognosis and treatment is the same as for the most common type of ovarian cancer, which is epithelial ovarian cancer.
The median survival of primary peritoneal carcinomas is usually shorter by 2–6 months time when compared with serous ovarian cancer.