You are in: eMedicine Specialties > Radiology > OBSTETRICS/GYNECOLOGY Ovary, Malignant TumorsArticle Last Updated: Apr 21, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 8
  Author: Arthur C Fleischer, MD, Professor, Chief of Diagnostic Sonography, Departments of Radiology and Obstetrics/Gynecology, Vanderbilt University Medical Center Arthur C Fleischer is a member of the following medical societies: American Institute of Ultrasound in Medicine Coauthor(s): Eugene C Lin, MD, Clinical Assistant Professor of Radiology, University of Washington Medical School Editors: Harris L Cohen, MD, FACR, Vice Chairman/Associate Chairman (Research Activities), Director, Division of Body Imaging, Professor of Radiology, Stony Brook School of Medicine; Visiting Professor of Radiology, Johns Hopkins School of Medicine; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Karen L Reuter, MD, FACR, Professor, Department of Radiology, Lahey Clinic Medical Center; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Lawrence M Davis, MD, Assistant Professor of Diagnostic Imaging (Clinical), Department of Diagnostic Imaging, Warren Alpert Medical School at Brown University Author and Editor Disclosure Synonyms and related keywords: ovarian cancer, ovarian tumor, ovarian carcinoma, ovarian malignancy, primary ovarian cancer, ovarian neoplasm, gynecologic malignancy, gynecologic cancer INTRODUCTIONSection 2 of 8
  BackgroundOvarian cancer is a silent killer; however, recent improvements in identification of women at high risk for ovarian cancer, as well as improved imaging techniques, increase the likelihood of early detection. For excellent patient education resources, visit eMedicine's Cancer and Tumors Center. Also, see eMedicine's patient education article Ovarian Cancer. PathophysiologyThe cause of ovarian cancer is not known. A connection between the number of ovulatory events and the risk of ovarian cancer appears to exist. Ovulation suppression has been shown to decrease cancer incidence. Most theories include the concept that ovarian cancer begins with the dedifferentiation of the cells overlying the ovary. During ovulation, these cells can be incorporated into the ovary, where they then proliferate. Ovarian cancer typically spreads to the peritoneal surfaces and omentum. Only an estimated 10% of affected patients have a genetic predisposition. The patients at highest risk are women with site-specific inheritance.1 In these patients, ovarian cancer develops early, when they are aged 30-50 years. Other risk factors include breast carcinoma. The identification of a genetic mutation for breast cancer suggests a greater risk for ovarian cancer. One study revealed that patients with the BRCA gene had a 60% risk of developing ovarian cancer. FrequencyUnited StatesIn the United States, the incidence of ovarian cancer is 33 cases per 100,000 women aged 50 years or older. The average patient age at diagnosis is 57 years. The lifetime risk is 1 case in 70 women, which is a 1.4% lifetime incidence. InternationalInternationally, the incidence is 3.1 cases per 100,000 women in Japan and 21 cases per 100,000 women in Sweden. Mortality/MorbidityOvarian cancer is the most deadly gynecologic malignancy, with an overall survival rate of approximately 35%. Approximately 60% of cases of ovarian cancer are lethal. The advent of techniques for earlier detection and more effective treatment may improve the overall survival rate.2, 3 RaceOvarian cancer is more common among American women in the white population than it is among those in the black population. SexOvarian cancer affects only females. AgeThe average patient age at presentation is 57 years. Women with a site-specific predisposition for ovarian cancer may present with symptoms when they are aged 30-50 years. AnatomyOvarian cancer spreads into the peritoneum, the omentum, and, in rare cases, the liver. Clinical DetailsNo specific signs or symptoms are observed in ovarian cancer. Some investigators report abdominal or pelvic swelling or pressure. Preferred ExaminationPelvic ultrasonography is the examination of choice, followed by magnetic resonance imaging (MRI) and/or computed tomography (CT) scanning.3, 4, 5 Limitations of TechniquesThe ovary may be difficult to delineate in some women who are postmenopausal because of its relatively small size (<2 × 2 cm), its position deep within the pelvis, and the lack of identifiable contained structures, such as cysts. DIFFERENTIALSSection 3 of 8
Pelvic Inflammatory Disease/Tubo-ovarian Abscess CT SCANSection 4 of 8
FindingsThe primary use of CT scanning is in the evaluation of metastatic disease rather than of the ovarian mass; for the evaluation of the ovarian mass, ultrasonography and MRI are more valuable.6 CT scanning is helpful in diagnosing cystic teratomas, 93% of which contain fat and 56% of which are calcified. If a large (>10 cm) soft-tissue mass is present, malignant transformation should be suspected.7 CT scanning also can aid in the evaluation of cystadenomas. A serous cystadenoma has an attenuation similar to that of water, whereas a mucinous cystadenoma has an attenuation closer to that of soft tissue. Degree of ConfidenceThe presence of wall and septal thickness and irregularity, as well as the existence of enhancing nodules, suggests malignancy. Although CT scan findings can suggest malignancy, they are not definitive for diagnosis unless metastases are present. False Positives/NegativesCT scan findings of complex functional cysts, benign ovarian tumors, and inflammatory and/or infectious masses, such as tubo-ovarian abscesses, can mimic ovarian malignancies. MRISection 5 of 8
FindingsThe primary advantage of using MRI in the evaluation of ovarian masses is the ability to employ this modality in the characterization of tissue. The presence of fat, hemorrhage, mucin, fluid, and solid tissue within an ovarian mass can be determined with the aid of MRI. The ability to characterize tissue in this way is most useful in determining whether a mass is definitely benign.6 To determine the potential of malignancy for epithelial tumors, assessing the internal architecture is useful. In this situation, for example, gadolinium enhancement can be employed in the differentiation of solid papillary tissue (which can enhance) from clot or debris (which does not). Gadolinium enhancement is useful in the evaluation of the internal architecture of predominately cystic lesions. In addition, if the mass is malignant, gadolinium enhancement may aid in the depiction of peritoneal implants. Obtain images in at least 2 planes with T1- and T2-weighted sequences.6 For masses with high signal intensity on T1-weighted images, the addition of fat-saturated, T1-weighted images is useful in differentiating fat from hemorrhage.6 Gadolinium enhancement is useful in evaluating the internal architecture of predominately cystic lesions. In addition, if the mass is malignant, gadolinium-enhancement may help to denote peritoneal implants. If the signal intensity of a lesion is high on the T1-weighted image, the lesion can contain fat, hemorrhage, or mucin. If the lesion loses signal intensity after fat saturation, it contains fat; most likely, it is a cystic teratoma. If it does not lose signal, the lesion most likely contains hemorrhage, and it may represent an endometrioma or hemorrhagic cyst. Endometriomas are often dark on T2-weighted images.8 In addition, high-viscosity mucin can be bright on T1-weighted images. Low-viscosity mucin is dark on T1-weighted images.9 If a lesion is dark on T1- and T2-weighted images, it may contain fibrotic tissue and be a fibroma. Consider a fibrothecoma or Brenner tumor. Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or magnetic resonance angiography (MRA) scans. Degree of ConfidenceIn a multivariate analysis, the accuracy of gadolinium-enhanced MRI in the diagnosis of ovarian malignancy was 93%.10 The findings most predictive of malignancy were necrosis in a solid lesion (odds ratio, 107) and vegetations in a cystic lesion (odds ratio, 40). In addition, ancillary findings, such as ascites, peritoneal metastases, and hemorrhage, on MRI scans had a high predictive value for malignancy. The use of gadolinium-based contrast agents improves tissue characterization and increases the degree of confidence for MRI findings. False Positives/NegativesAs with CT scans, MRI scans may depict numerous benign processes, such as complex functional cysts, tubo-ovarian abscesses, and benign tumors, that can mimic an ovarian malignancy. ULTRASONOGRAPHYSection 6 of 8
FindingsMalignant ovarian tumors tend to have papillary excrescences, irregular walls, and/or thick septations.1, 3, 6, 11, 12 The tumor can contain echogenic material arising from mucin or protein debris. The more solid the areas are, the greater the likelihood that a tumor is present. Typically, intraperitoneal fluid is present; this is a sign of peritoneal spread. On color Doppler ultrasonograms, tumors tend to have vessels with low impedance because of the lack of muscular media in the vessel wall and arteriovenous shunts. The vessels tend to be clustered. Degree of ConfidenceThe ultrasonographic finding that is most indicative of ovarian cancer is papillary excrescence, which is present in more than 50% of ovarian malignancies. Low impedance and clustered vessels have a 70-80% diagnostic accuracy.5 False Positives/NegativesTubo-ovarian abscesses may mimic the ultrasonographic appearance of ovarian cancer, but patients with abscesses typically present with symptoms that are attributable to an inflammatory process. MULTIMEDIASection 7 of 8
REFERENCESSection 8 of 8
Ovary, Malignant Tumors excerpt Article Last Updated: Apr 21, 2008 | ||||||||||||||||||||||||||||||||||||||||||
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