The diagnosis of ovarian cancer is usually made at laparotomy, but occasionally at laparoscopy. If a pelvic mass is suspicious and the most likely diagnosis is ovarian cancer, surgery should not be unnecessarily delayed. In premenopausal patients, however, predominantly cystic pelvic masses can be observed over a period of 1 to 2 months. Lesions that are essentially mobile, are unilateral, and have a smooth contour are much less likely to be neoplastic, and are unlikely to be malignant. In premenopausal patients with cystic lesions of less than 8 cm, attempted suppression with oral contraceptives is indicated. In women who are definitely postmenopausal, cystic masses larger than 5 cm should be removed unless they represent a chronic finding. Those masses that regress in size can be managed with continued observation, whereas those that persist or enlarge must be evaluated surgically. Conversely, patients whose lesions are irregular, predominantly solid, and somewhat immobile should undergo an exploratory laparotomy.

The preoperative evaluation of patients can be aided by the use of CA125. Elevated CA125 levels are most frequently associated with malignant adnexal masses in postmenopausal women. In women over 50 years of age whose serum CA125 level is greater than 35 U/mL the adnexal mass is malignant in about 80% of cases. A CA125 of more than 95 U/mL is associated with a positive predictive value of 96% in this setting. Conversely, the majority of premenopausal women with serum CA125 levels greater than 35 U/mL have benign conditions, such as uterine myomata, endometriosis, and benign ovarian tumors. Elevation of serum CA 125 in a postmenopausal patient with a pelvic mass should prompt exploration by surgeons prepared to undertake complete staging and, if necessary, cytoreductive operations.

Ultrasonographic signs of malignancy include an adnexal pelvic mass with areas of complexity, such as irregular borders; multiple echogenic patterns within the mass; and dense, multiple irregular septae. Bilateral tumors are more likely to be malignant, although the individual characteristics of the lesions are of greater significance. Transvaginal ultrasonography may have a somewhat better resolution than transabdominal ultrasonography for adnexal neoplasms. Newer techniques using Doppler color flow imaging may enhance the specificity of ultrasonography for demonstrating findings consistent with malignancy.

Radiographic techniques, including abdominal radiographs, computed tomography (CT) scans, and nuclear magnetic resonance imaging (MRI), are not useful prior to the surgical diagnosis of ovarian cancer.93 The preoperative evaluation of patients who have a suspicious pelvic mass can omit these studies when blood chemistries and enzymes suggest normal hepatic and pancreatic function.52 In patients with ascites and no pelvic mass, however, a CT or MRI may be useful in identifying other potential sites of origin. Paracentesis is not recommended because of the frequency of metastatic implantation and growth in the needle tract. Liver-spleen scans, brain scans, and bone scans are unnecessary unless specific symptoms suggest metastasis to these sites.

In premenopausal women, radiographic studies of the intestines are not required unless there is the finding of occult blood in the rectum or there are symptoms indicating upper or lower intestinal obstruction. A barium enema or endoscopy is appropriate in postmenopausal patients. Mammography should be performed to exclude primary breast cancer, which can coexist with ovarian cancer or spread to the ovaries. Cervical cytology should be performed, although ovarian cancer cells are unlikely to exfoliate through the uterus to the cervix. In patients with irregular or heavy menses, an endometrial biopsy should be performed to exclude primary endometrial pathology.

The differential diagnosis of an adnexal mass includes a variety of functional changes of the ovary, benign neoplasms of the reproductive tract, and inflammatory lesions of these organs. A hydrosalpinx, endometriosis, and pedunculated uterine leiomyomata can simulate an ovarian neoplasm. Nongynecologic diseases, such as inflammatory processes of the colon and rectum, must be excluded.