From the archives of the AFIP: radiologic staging of ovarian carcinoma with pathologic correlation.

Ovarian cancer is the deadliest gynecologic malignancy, with approximately 70% of patients having peritoneal involvement at the time of diagnosis. It spreads predominantly by direct invasion and intraperitoneal dissemination. The staging system is surgically based, with stage I disease being limited to one or both ovaries. In stage II disease, there is extraovarian spread of tumor, but it does not extend beyond the pelvis. Stages III and IV disease are considered advanced, with stage III ovarian cancer including diffuse peritoneal disease involving the upper abdomen and stage IV disease having distant metastases including hepatic lesions. Common sites of intraperitoneal seeding include the omentum, paracolic gutters, liver capsule, and diaphragm. Thickening, nodularity, and enhancement are all signs of peritoneal involvement. Although computed tomography is the most common imaging modality used to stage ovarian cancer, magnetic resonance imaging has been shown to be equally accurate. Currently, however, no imaging modality allows microscopic spread of disease to be ruled out, and a full staging laparotomy is always required. Early ovarian cancer is treated with comprehensive staging laparotomy, whereas advanced but operable disease is treated with primary cytoreductive surgery (debulking) followed by adjuvant chemotherapy. Patients with unresectable disease may benefit from neoadjuvant (preoperative) chemotherapy before debulking.