The finding of a pelvic mass may occur in a female patient of any age; fortunately, most masses are associated with a benign neoplasm or process. Nevertheless, each year, between 5% and 10% of women in the United States undergo surgery for a suspected ovarian neoplasm; only 13% to 21% of these women prove to have a malignant ovarian neoplasm.1
A pelvic mass may be found on an abdominal or pelvic examination in an asymptomatic patient at a scheduled health maintenance assessment or on examination of a symptomatic patient who presents with a complaint. A mass may also be noted as an incidental finding on imaging studies, usually computed tomographic scans of the abdomen or pelvis or pelvic ultra-sonography, obtained either for medical indications unrelated to a suspected pelvic disease or as a screening study for gynecologic malignancies. Increasingly, a pelvic mass is found on imaging studies obtained in the emergency department for the evaluation of vague abdominal pain or trauma.2
The differential diagnosis is extensive [see Table 1], because a pelvic mass may be of gynecologic or nongynecologic origin and may be associated with congenital, functional, neoplastic (either benign or malignant), obstructive, or inflammatory processes; a mass may also be associated with pregnancy. When a mass is of gynecologic origin, it may arise from the ovary, fallopian tube, broad ligament, round ligament, uterus, cervix, or uterosacral ligament. Adnexal masses arise from an area comprising the ovary, the fallopian tube, and the ligaments of the uterus. When the mass is of nongynecologic origin, it may arise from the urinary tract system, the gastrointestinal system, or the pelvic vessels or nerves. Rarely, a mass may arise directly from the peritoneum, the retroperitoneum, or the omentum.
The possible etiologies differ markedly, depending on the patient’s age and symptoms. Consequently, the complete documentation of symptoms; the past medical, family, and surgical histories; the physical examination; and the initial imaging studies and laboratory tests will narrow the differential diagnosis and direct appropriate evaluation and referral. The overview of the diagnostic evaluation is presented [see Evaluation of the Patient with a Pelvic Mass, below], followed by a review of the distinctions in diagnostic workup required for patients of each age group [see Age-Specific Considerations in Patient Evaluation, below].
Evaluation of the Patient with a Pelvic Mass
Medical history
The patient’s medical history is essential in the evaluation of a pelvic mass; it includes a complete menstrual history, which establishes menarche and cyclicity of menses. Because ovulation generally occurs midcycle, a new pelvic mass found midcycle could be consistent with a functional cyst, whereas a mass identified later in the cycle would be more consistent with a corpus luteum cyst. A patient with a long history of irregular menses or even secondary amenorrhea with nontender bilateral adnexal masses may have polycystic ovaries. Pelvic inflammatory disease usually presents about a week after menstruation, and missed menses suggest a pregnancy. Therefore, an accurate menstrual history is useful in directing the patient evaluation.
Menstrual Bleeding
Increased menstrual bleeding often occurs with submucous leiomyomas. Postmenopausal bleeding may be caused by en-dometrial cancer or, rarely, by hormonally functioning ovarian or fallopian tube neoplasms. Irregular bleeding, pain, and missed menses suggest an ectopic pregnancy.
Although rare, estrogen-producing neoplasms may cause abnormal uterine bleeding, breast tenderness, or hirsutism. In children, precocious puberty may develop.
In women of reproductive age, the medical history must include questions about contraceptive practices, because a patient on oral contraceptive pills is less likely to develop physiologic and functional cysts (e.g., follicular and corpus luteum cysts). In addition, a patient with multiple sexual partners who does not use barrier contraception may develop pelvic inflammatory disease and a chronic tubo-ovarian abscess.
Abdominal Pain
Pain, if present, must be characterized. The onset, pattern of occurrence, and extent or severity of pain may give important indications of the etiology of the suspected pelvic mass. For example, new onset of midcycle pain in premenopausal women suggests the presence of a physiologic cyst. Pain following intercourse may be related to a ruptured cyst, whereas chronic pain during intercourse is suggestive of endometriosis.
Acute pain Acute severe abdominal or pelvic pain accompanies torsion of an adnexal structure or pedunculated leiomyoma (in which case the pain is usually intermittent); hemorrhage or rupture of an ovarian cyst; dilation of the fallopian tube in association with an ectopic pregnancy; or rupture of a pelvic abscess. In addition, a degenerating leiomyoma may also cause acute pain. The rapid stretching of the ovarian capsule by an expanding functional cyst or germ cell neoplasm may produce acute pain.
Chronic, cyclic pain More chronic, cyclic pain, particularly pain associated with dysmenorrhea, dyspareunia, and menor-rhagia, suggests endometriosis. In addition, chronic pelvic or abdominal discomfort is often reported with long-standing tubo-ovarian abscesses or chronic hydrosalpinx. Chronic abdominal pain or vague abdominal discomfort accompanied by bloating suggests an ovarian neoplasm.
Changes in Bowel Habits
Changes in bowel habits and constitution, as well as changes in appetite, weight, and energy, may be more consistent with a benign colonic disease or with a cancer arising in any pelvic organ. The medical history of gynecologic cancers or precancerous disease, breast cancer, melanoma, or any cancer may direct the workup. The family history is important, because hereditary cancers, such as those associated with a BRCA1 or BRCA2 mutation (e.g., breast, ovary, endometrial cancer), or nonpolyposis colon cancer may present as a pelvic mass.
Physical examination
Before the pelvic examination, the patient should empty her bladder. There must be adequate light for a visual inspection of the external genitalia for signs of androgen excess. The vagina and cervix must be inspected for signs of infection and hormones. A Papanicolaou smear should be obtained if the patient’s age and findings on physical examination indicate the need for it. The abdominovaginal examination gives information on the size, shape, consistency, location, mobility, laterality, and tenderness of the mass. This information must be confirmed by the rectovaginal examination, which also evaluates the uterosacral ligaments, the cul-de-sac, and the anorectal area. Physical examination may suggest whether the mass is benign or malignant [see Table 2]. When a pelvic mass is identified, a complete physical examination must be performed. Particular attention should be paid to the examination of the breasts, the respiratory system, the nodal areas, and the abdomen.
Laboratory tests
In the evaluation of a pelvic mass, especially in women of reproductive age, a urinary or serum |-human chorionic gonadotropin (|-hCG) test is required. To determine pregnancy, the urinary test is adequate at the time of missed menses. This test, however, is qualitative in nature, and for the management of an ectopic pregnancy or molar pregnancy, a quantitative determination of the | -hCG serum concentration is necessary. In addition to being an indication for pregnancy, elevated levels of | -hCG may be associated with theca-lutein cysts, especially in women with choriocarcinoma, diabetes mellitus, and Rh sensiti-zation; elevated levels of | -hCG are also associated with clomi-phene use, human menopausal gonadotropin or human chori-onic gonadotropin ovulation induction, and use of gonadotro-pin-releasing hormone analogues.3
A complete blood count will help in assessing anemia; an elevated white cell count suggests an infectious etiology. The ery-throcyte sedimentation rate is nonspecific and does not narrow the differential diagnosis.
Imaging studies
The most important initial diagnostic tool in evaluating a pelvic mass is the pelvic ultrasound, which indicates whether the mass is more likely to be uterine, adnexal, or gastrointestinal in origin. A pelvic ultrasound scan also provides information on the size and consistency of the mass—characteristics that suggest whether the mass is malignant or benign.
Unilocular ovarian cysts are overwhelmingly benign and resolve spontaneously in 3 to 6 months; therefore, observation is the recommended approach to management. If malignancy is suspected on pelvic ultrasound, additional imaging studies such as abdominal pelvic computed tomography or magnetic resonance imaging may assist in confirming the diagnosis. The CT scan may further characterize the malignant potential of the mass and give information regarding evidence of metastatic spread to lymph nodes, the retroperitoneal space, or adjacent structures. If the origin of the pelvic mass is uncertain, an MRI may help clarify whether the mass arises from the uterus, ad-nexa, or another structure (e.g., muscles or nerves).
|
Table 1 Differential Diagnosis of Pelvic Mass |
|
|
Ovary |
Gastrointestinal tract |
|
Functional cyst |
Bowel loops with feces |
|
Endometrioma |
Diverticular disease |
|
Benign neoplasm |
Inflammatory bowel disease |
|
Malignant neoplasm |
|
|
Fallopian tube |
Appendicitis |
|
Tubo-ovarian abscess |
Benign small bowel neoplasm |
|
Hydrosalpinx |
|
|
Paratubal cyst |
Colon cancer |
|
Ectopic pregnancy |
Urinary tract |
|
Distended bladder |
|
|
Benign neoplasm |
|
|
Pelvic kidney |
|
|
Malignant neoplasm |
|
|
Urachal cyst |
|
|
Uterus |
|
|
Fibroid (pedunculated or |
Retroperitoneum |
|
interligamentous) |
Abdominal wall hematoma or abscess |
|
Intrauterine pregnancy |
|
|
Sarcoma, lymphoma, or teratoma |
|
|
Sarcoma |
|
|
Benign neoplasm |
|
Ultrasound
Transabdominal and transvaginal ultrasound Two methods of ultrasound provide extensive information about the characteristics of a pelvic mass. Transabdominal ultrasound is better tolerated by patients than is transvaginal ultrasound, and it gives more information about abdominal processes. Transvagi-nal ultrasound, however, provides better resolution and more precise information of the mass within the pelvic organ. The unique imaging patterns offered by each of these ultrasound modalities frequently help narrow the differential diagnosis.
Physiologic ovarian cysts are usually oval and filled with clear fluid. They may or may not have septations, and they have no echogenic or solid components, with the exception of the corpus luteum. Cystic teratomas are partially cystic and solid with echogenic foci of abnormal tissue from foreign tissues and hemorrhage. Endometriomas are simple cysts with echogenic elements secondary to old and new hemorrhage. Leiomyomas are solid or semisolid, well-circumscribed masses; they are similar in appearance to the myometrium but have no vascular vessels within the mass.
Several morphologic scoring systems have been introduced to predict whether a pelvic mass evaluated by ultrasound is benign or malignant. Most systems agree that the following characteristics are suggestive of malignancy: irregularity in the wall of the mass, the presence of thick septations within the mass, any papillary projection within or emerging from the mass, and a mass containing solid components. Size itself is an important characteristic; a mass larger than 8 cm in diameter raises concern. In general, the more of these characteristics that are present, the greater the chance that the mass is malignant.
Color Doppler ultrasound The use of color flow Doppler imaging may help in determining whether the adnexal mass is malignant or benign, because malignancies have an increased neovascularity and, thus, lower resistance and pulsatile indices. Currently, there is no agreement concerning pulsatile indices that indicate malignancy; nevertheless, specific indices may be less important in suggesting malignancy than overall morphologic pattern, blood flow, and tumor location.
Taking into consideration the findings of regular and color flow ultrasound, the overall sensitivity, using morphologic criteria for malignant disease, ranges from 82% to 100%; specificity ranges from 60% to 95%. It is unclear, however, whether the addition of the color flow Doppler significantly improves these percentages. Two large studies reported that the combined approach (using regular and color flow ultrasound) has a sensitivity of 88% to 97%, a specificity of 97% to 100%, and an accuracy of 83% to 99%.4
Computed tomography CT is less frequently used in the initial evaluation of a pelvic mass than other imaging studies. However, the sensitivity, specificity, and accuracy of CT for determining whether the mass is benign or malignant is reported to be comparable to other modalities (i.e., sensitivity, 89%; specificity, 96% to 99%; accuracy, 92% to 94%).4 CT is better than ultrasound in assessing the retroperitoneal spaces (i.e., nodal systems, pancreas, and spleen) and the omentum. CT is useful in establishing the extent of intra-abdominal and retroperitoneal disease in patients in whom an ovarian malignancy is highly suspected.
Magnetic Resonance Imaging
MRI may be used in the evaluation of a pelvic mass when findings from ultrasound studies are unclear or indeterminate. MRI is particularly useful in clarifying the origin of the mass as either uterine or ovarian. In addition, its accuracy in assessing fatty and hemorrhagic components of a mass can help in the diagnosis of dermoid cysts, hemorrhagic corpus luteum cysts, and endometriosis. This modality may be especially useful in the pregnant patient, if more information is needed than is provided by the pelvic ultrasound.5
Positron Emission Tomography
Positron emission tomography (PET) has limited application in the initial evaluation of pelvic masses. It is used primarily to detect recurrent pelvic malignancies.
Serum tumor markers
Serum tumor markers are not used for screening; they are used in the evaluation of patients with suspected malignant pelvic neoplasms. In deciding which serum markers to use, consideration must be given to the patient’s age and medical history. For instance, in prepubertal girls and young women, germ cell tumors are the most frequent ovarian malignancy; appropriate serum markers for suspected germ cell tumors include a-fe-toprotein (AFP), lactate dehydrogenase (LDH), and |-hCG. In older women with suspected malignancy, it is important to measure epithelial tumor markers, such as CA125. In patients with confirmed malignancy, a significant elevation in the level of a tumor marker may indicate malignant recurrence, whereas decreasing levels reflect response to treatment. Functional ge-nomics and proteomics—the study of human gene sequences and protein sequences, respectively—show promise in identifying novel cellular targets that may be exploited in the future as screening tests for cancer.
Table 2 Physical Findings Associated with Pelvic Mass
|
Characteristic of Mass |
Suggestive of Benign Process |
Suggestive of Malignant Process |
|
Unilateral |
Yes |
Occasionally |
|
Bilateral |
Occasionally |
Yes |
|
Cystic |
Yes |
No |
|
Solid |
No |
Yes |
|
Mobile |
Yes |
Occasionally |
|
Fixed |
Occasionally |
Yes |
|
Irregular contour |
Occasionally |
Yes |
|
Smooth contour |
Yes |
No |
|
Presence of ascites |
No |
Yes |
|
Cul-de-sac nodules |
Usually no |
Yes |
|
Rapid growth rate |
No |
Yes |
|
Pain |
Yes |
Usually no |
|
Size |
< 5 cm |
a 10 cm |
Measurement of AFP, LDH, and ft-hCG
Dysgerminomas are the most common germ cell tumors and can occur at any age; these malignancies are associated with elevations in AFP, LDH, and | -hCG. Placental alkaline phospha-tase and LDH levels are sometimes elevated in patients with dysgerminomas. Endodermal sinus tumors can be monitored by measuring AFP levels, and choriocarcinomas can be monitored by measuring | -hCG levels. Embryonal carcinoma may secrete both AFP and | -hCG. Immature teratomas usually do not secrete any markers. Mixed germ cell tumors may secrete combinations of the above markers. Granulosa cell tumors are associated with elevated levels of inhibin and estradiol in prepu-bertal and postmenopausal women.
Measurement of CA125
CA125 is a glycoprotein expressed by fetal amniotic and coelomic epithelium and mullerian epithelium. Elevated levels of serum CA125 may suggest an increased risk of malignancy in certain patients; however, elevations of CA125 are also associated with normal and benign conditions. Therefore, CA125 measurement is not useful as a screening test for ovarian cancer. A CA125 serum concentration greater than 35 U/ml is found in 83% of patients with epithelial ovarian cancer, but it is reported to be elevated in only 50% of patients with stage I disease that is limited to the ovary.6 In addition, CA125 is increased in patients with other malignancies; in those with benign gynecologic conditions; and in patients with diverticulitis and cirrhosis. It is also increased in normal conditions of pregnancy and menstruation [see Table 3].7 Approximately 1% of healthy women have elevated CA125 serum levels.8 In women with benign gynecologic conditions, the levels are usually less than 200 U/ml.
In postmenopausal women, CA125 measurement may have some application as a screening test for malignancy but is not a routine screening test. In a prospective Swedish study of 4,290 volunteer women who were at least 50 years of age, the specificity of CA125 measurement for ovarian cancer was reported to be 97% and the positive predictive value was 4.6%, using a CA125 level greater than 30 U/ml.9 However, an elevated CA125 level in postmenopausal women with a pelvic mass suggests a malignancy. The positive predictive value for elevations of CA125 in this age group has been reported to be 97%.10 In women of reproductive age, elevations of serum CA125 may raise the suspicion of malignancy when imaging findings (i.e., tumor location, morphologic pattern, and vascularity) are also consistent with malignancy.
Table 3 Conditions Associated with an Elevated Serum CA125 Level
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Gynecologic malignancies |
Epithelial ovarian cancers |
|
Germ cell cancers |
|
|
Sex chord stromal tumors |
|
|
Fallopian tube cancers |
|
|
Endometrial cancers |
|
|
Adenocarcinoma of the cervix |
|
|
Benign gynecologic conditions |
Adenomyosis |
|
Benign ovarian neoplasms |
|
|
Endometriosis |
|
|
Functional ovarian cysts |
|
|
Leiomyomas |
|
|
Meigs syndrome |
|
|
Menstruation |
|
|
Pregnancy |
|
|
Ovarian hyperstimulation |
|
|
Pelvic inflammation |
|
|
Nongynecologic conditions |
Liver disease and cirrhosis |
|
Colitis |
|
|
Congestive heart failure Diabetes |
|
|
Diverticulitis |
|
|
Lupus |
|
|
Mesothelioma |
|
|
Pericarditis |
|
|
Polyarteritis nodosa |
|
|
Surgery |
|
|
Previous irradiation |
|
|
Renal disease |
|
|
Sarcoidosis |
|
|
Tuberculosis |
|
|
Nongynecologic cancers |
Breast |
|
Colon |
|
|
Lung |
|
|
Pancreas |
|
|
Lymphoma |
