- Psammomacarcinoma is a rare histologic subtype of serous carcinoma originating in the ovary or peritoneum, characterized by massive psammoma body formation, invasiveness, and low-grade differentiation. Its clinical behavior appears similar to that of serous borderline tumors rather than that of typical invasive serous carcinomas. Peritoneal psammomacarcinoma is even rarer than its ovarian counterpart with only 10 cases have previously been documented in the literature. A case of F.I.G.O. stage IIIC peritoneal psammomacarcinoma is described. Optimal debulking surgery, including omentectomy, total abdominal hysterectomy, bilateral adnexectomy, and resection of segment of jejunum, was performed. The patient received adjuvant chemotherapy with taxol and cisplatin, and to date, 15 months after surgery, she is alive and with no evidence of disease. It is concluded that peritoneal psammomacarcinoma is a very rare tumor that behaves less aggressively than typical serous carcinoma. The mainstay of treatment is surgical debulking. The role of adjuvant chemotherapy has as yet not been established.