Primary peritoneal carcinoma: overview, diagnosis, treatment, and distinctions

Characteristics and pathology

PPC typically produces widespread, thin, sheetlike tumor deposits on peritoneal surfaces rather than forming a large, discrete mass. Under the microscope most tumors show serous papillary architecture and may contain psammoma bodies. Immunohistochemical staining often overlaps with serous ovarian tumors (for example, positivity for WT1 and cytokeratins), which is why it is regarded as closely related to ovarian serous carcinoma.

Symptoms and clinical presentation

Symptoms are generally non‑specific and stem from involvement of the abdominal cavity: increasing abdominal girth or bloating from ascites, pelvic or abdominal pain, early satiety, anorexia, and unexplained weight changes. Because these features are common to many intra‑abdominal conditions, diagnosis is frequently delayed until imaging or operative assessment reveals diffuse peritoneal disease.

Diagnosis and staging

Evaluation typically combines physical examination, cross‑sectional imaging (ultrasound, CT or MRI), measurement of tumor markers such as CA‑125, and direct tissue sampling by laparoscopic or open biopsy. Pathologic criteria distinguish PPC from ovarian primary tumors when the ovaries are normal in size or only minimally involved while the peritoneum shows extensive tumor. Staging and clinical decision‑making follow protocols used for epithelial ovarian cancer; for related clinical information see ovarian cancer.

Treatment and prognosis

Management mirrors that of advanced epithelial ovarian cancer: a combination of cytoreductive surgery aimed at removing visible tumor and platinum‑based combination chemotherapy (commonly a taxane plus a platinum agent). The overall response rates and management strategies are similar to those for serous ovarian carcinoma, although many reports suggest median survival may be modestly shorter by a few months in some series. Individual prognosis depends on stage at diagnosis, completeness of surgical cytoreduction, performance status and tumor biology, including BRCA mutation status which can affect chemosensitivity and options for targeted therapy.

History, epidemiology and notable distinctions

• PPC is relatively uncommon compared with ovarian carcinoma but is an established clinical entity recognized in gynecologic oncology.
• It can arise even after removal of the ovaries (for example, after risk‑reducing salpingo‑oophorectomy), which underscores that the peritoneal surface itself is the primary site.
• Because of its close relationship to serous ovarian cancer there is overlap in genetic risk factors (for example BRCA1/2), treatment approaches and clinical trials.

Awareness of PPC is important for prompt diagnosis and appropriate management, especially in patients with persistent abdominal symptoms and a history of genetic risk for serous carcinomas.