Obstetrics and Gynecology

Adnexal/pelvic mass

Adnexal/Pelvic Mass (Ovarian Mass, Ovarian Cyst)

1. Epidemiology, Signs and Symptoms

In the United States, the diagnosis of an adnexal or pelvic mass will occur in five to ten percent of women in their lifetime. Although commonly benign, a small percentage (15 to 20 percent) will be malignant and diagnosis of these at the earliest possible stage is of critical importance. The risk for malignancy in an adnexal or pelvic mass increases with age.In general, postmenopausal women are at greater risk than premenopausal women. Even if not cancerous, some adnexal or pelvic masses can be problematic because of their size, proximity to critical organs or emergency presentations such as torsion. Adnexal or pelvic masses can present in many different ways.

Although some clinical presentations can be dramatic, such as ovarian torsion, in the majority of women, symptoms are absent and the mass is encountered during an examination or during the performance of an imaging study for gynecologic indications or as an incidental finding when performing a study for another unrelated indication. The most common symptoms encountered in a patient with an adnexal or pelvic mass are abdominal fullness, abdominal bloating, pelvic pain, difficulty with bowel movements, and increased frequency of urination, abnormal vaginal bleeding, or pelvic pressure.

Some patients will present with only one of these symptoms. while others may have a combination of two or more. For those patients in whom an asymptomatic adnexal or pelvic mass is discovered, it is most commonly encountered radiologically. Pelvic examinations are limited in their ability to identify an adnexal or pelvic mass; only with the larger masses may patients have a visible bulge in the lower abdomen.

2. Diagnosis and differential diagnosis

The presence of a pelvic or adnexal mass, as stated earlier, is most commonly demonstrated on an imaging study for either gynecologic or other unrelated issues. Imaging studies are most commonly performed in response to symptoms rather than concern on a pelvic or abdominal exam. All women who present with symptoms of abdominal bloating or distention, abnormal bleeding, change in bowel or bladder habits, pelvic pressure, or pelvic pain or any combination of these symptoms should first undergo a thorough physical examination, including a pelvic examination.

The pelvic examination of the patient should include a speculum examination as well as a bimanual and rectovaginal examination. Masses are not always palpable, but if present, documenting the nature of the mass, including its size, laterality, contour, mobility, presence or absence of tenderness, and location, is important in guiding future surgical decision making as well as contributing to the differential diagnosis. Acute tenderness on examination may indicate ovarian torsion or ectopic pregnancy. A nodular or fixed mass may be suspicious for cancer.

The differential diagnosis for the pelvic or adnexal mass is extensive. It is important to remember that not all adnexal or pelvic masses are of gynecologic origin and to keep other possibilities in the differential. Table I is a list of the common differential diagnosis of benign masses, and Table II lists the malignant differential.

Table I.

Benign Masses
Gynecologic Nongynecologic
Functional Cyst Paratubal Cysts
Uterine Fibroids Diverticular Abscess
Endometrioma Nerve Sheath Tumors
Tubo-ovarian Abscess Urinary Tract Diverticula
Hydrosalpinx Pelvic Kidney
Mucinous Cystadenoma Inclusion Cyst
Serous Cystadenoma Appendiceal abscess
Mature Cystic Teratoma
Ectopic Pregnancy

Table II.

Malignant Masses
Gynecologic Nongynecologic
Ovarian Cancer Colon/Rectal Cancers
Fallopian Tube Cancer Appendiceal Cancer
Endometrial Cancer Retroperitoneal Sarcomas
Uterine Sarcoma Metastatic Cancers

The most commonly performed imaging study for the suspicion of a pelvic mass is an ultrasound. It is recommended that transvaginal as well as transabdominal ultrasound be performed whenever possible. Transvaginal imaging has been demonstrated to be superior to other imaging techniques for evaluation of a pelvic mass and allows for the specific characterization of the mass as close as possible to its actual gross appearance. The descriptive characteristics for an ultrasound report should include the size, consistency, laterality, internal and external wall characteristics, and commentary on the presence or absence of pelvic fluid.

The consistency of a mass is described as solid, cystic, or mixed. The laterality should describe whether the process is unilateral or bilateral. The internal and external wall characteristics would generally be described as mural nodules internally or papillary excrescences, while pelvic fluid should be described as absent, physiologic, or ascites. The addition of color Doppler to the routine transvaginal ultrasound gives information about blood flow in and around a mass. In theory, tumors will attract low resistance, high flow vessels. Commentary on the architecture of the surrounding vessels is also important. In general, for both pre- and post-menopausal women, the presence of mural nodules, excrescences, and ascites is suspicious for a malignancy, while simple cystic masses without associated pelvic fluid are usually benign.

Characteristics of other benign lesions including endometriomas, mature teratomas, corpus luteum cysts, and hydrosalpinges may be helpful in the management of these pelvic masses. Endometriomas typically appear as a round homogeneous appearing cyst containing internal low level echoes. Mature teratomas may contain a hypoechoic mass with hyperechoic nodules (Rokitansky nodule or dermoid plug), calcifications, hyperechoic lines, or fat/fluid levels in descending order of frequency. Corpus luteum cysts have a classic "ring of fire" rim of vascularity on color Doppler. Hydrosalpinges appear as tubular shaped sonolucent cysts.

There have been attempts to develop predictive ultrasound indices that combine the different characteristic to yield a prediction for the presence or absence of a malignancy. In large studies, however, these indices have demonstrated sensitivities in the 80 to 90 percent range with specificities ranging from 60 to 80 percent. Unfortunately, these numbers are not greatly different from individual serum markers.

Additional imaging studies include computed tomography, magnetic resonance imaging, and positron emission tomography. In general, the use of these imaging modalities is not recommended in the frontline evaluation, but can play a valuable role in the remainder of the workup as indicated. Computed tomography can be helpful in evaluating for the presence of extrapelvic metastasis when the initial evaluation is concerning for the possibility of a malignancy. Magnetic resonance imaging can be helpful in attempting to further distinguish between a uterine versus an adnexal mass, especially in the setting of solid masses adjacent to the uterus on imaging that may prove to be a uterine fibroid.

Serum marker screening can play a significant role in the further evaluation of a pelvic mass. These include studies that may be helpful in determining the nature of mass as well as new developments in multiple marker studies to help stratify risk and direct the patient to the most appropriate surgical strategy. The most commonly used marker is CA-125, a serum protein. CA-125 elevations can be seen with uterine fibroids, endometriosis, pelvic inflammatory disease, cirrhosis, pregnancy and menstruation. However, CA-125 can also be elevated in ovarian, peritoneal, fallopian tube, and endometrial cancers. CA-125 elevation can be seen in 80 percent of epithelial ovarian cancers, although only in 50 percent of stage I ovarian cancers.

Although sensitive for the presence of an advanced malignancy, elevations in CA-125 in multiple benign conditions and the low sensitivity for early stage ovarian cancer make CA-125 an ineffective screening test for the general population. Other markers include beta-HCG, LDH (lactate dehydrogenase), and AFP (alpha-fetoprotein), which may be elevated in certain germ cell tumors, while inhibin A and/or B levels are markers for granulosa cell tumors of the ovary. It is also important to rule out pregnancy when presented with an adnexal or pelvic mass by obtaining a pregnancy test in patients of childbearing age.

The most effective diagnostic approach is a combination of physical examination, imaging and serum marker assessment. In an effort to better delineate the location of surgery for a pelvic mass, the Society of Gynecologic Oncologists (SGO) and the American College of Obstetricians and Gynecologists (ACOG) proposed referral guidelines in 2005.

Utilizing these guidelines can increase the likelihood that a woman with ovarian cancer will have her surgery performed at a tertiary referral center with gynecologic oncology expertise as this has been shown to improve outcomes for women with this type of cancer. Premenopausal women with CA-125 levels greater than 200 units/ml, ascites, evidence of abdominal or distant metastasis on exam or imaging, or a family history of breast or ovarian cancer and postmenopausal women with any elevated CA-125 level, ascites, a fixed or nodular mass, evidence of abdominal or distant metastasis, or a family history of breast or ovarian cancer meet these guidelines and should be referred to a tertiary center.

In the relatively recent past, two tests that combine multiple biomarkers have been cleared by the Food and Drug Administration (FDA) for use in guiding clinicians regarding referral to a tertiary center. The more recent, ROMA, utilizes CA-125 and HE-4 in combination, while OVA-1 utilizes five immunoassays. The results of these tests place women in to high and low risk categories for a malignancy and can help guide clinicians in referral decision making. One important distinction is that these tests are only approved for determining where a surgery should be performed after the decision to operate has been made. They are not approved as screening tests nor are approved to decide whether a surgery is necessary.

3. Management

Deciding between surgery and observation

To expedite the decision between operating and observing, the clinician should address the following two questions. Are there signs and/or symptoms of an acute abdomen? Are there signs and/or symptoms to suggest a malignancy?

In the setting of an acute abdomen, surgical intervention is usually always indicated; the most common causes of this type of presentation are ectopic pregnancy, ovarian torsion, and pelvic inflammatory disease. The surgical management is then guided by the causative factor, the extent of the problem, and the age of the patient.

In the acute setting, surgical therapy can be undertaken in two general approaches: either laparotomy (a large incision) or using minimally invasive techniques (laparoscopy or robotics). The decision to use one strategy or the other is based on surgeon preference, the stability of the patient and the extent of the problem. For instance, a patient with pelvic inflammatory disease with signs and or symptoms of sepsis would not be a candidate for minimally invasive surgical management, while the standard of care for a clinically stable patient with an ectopic pregnancy requiring surgery would be via laparoscopy.

In the setting of a mass suspicious for malignancy, surgeon preference and the extent of the problem are important guides. Although not a mandate, laparotomy is generally preferred when an advanced malignancy is suspected (ascites or extrapelvic findings on imaging) or the mass is too large for conventional minimally invasive techniques.

In the setting of an adnexal or pelvic mass that is considered likely to be benign, conservative management without surgery is preferred in the absence of symptoms that have a major impact on the quality of life of a patient. Ongoing conservative management strategies range from routine annual gynecologic follow-up to repeat imaging, repeat serum marker analysis or both imaging and serum marker follow-up.

In September, 2010, the Society of Radiologists in Ultrasound published a consensus statement in Ultrasound Quarterly regarding the management of asymptomatic ovarian and other adnexal cysts imaged on ultrasound. This was based on a consensus panel of specialists in gynecology, radiology, and pathology who convened in Chicago in October 2009.

Recommendations regarding the management of simple, hemorrhagic, endometriotic, and dermoid cysts of the ovary as well as hydrosalpinges and peritoneal inclusion cysts are outlined in detail in the document. Many of the recommendations lengthen the interval between or eliminate entirely further surveillance ultrasounds after a cyst is diagnosed. This effort has helped to streamline management for a frequently diagnosed finding.

The consensus statement also clearly indicates that cysts that have thick septations, nodules with blood flow, or focal areas of wall thickening have a substantial likelihood of malignancy. Surgical evaluation is strongly encouraged for these findings.

4. Complications

What complications could arise as a consequence of a particular management strategy?

Complications of management depend on the strategy pursued. Surgical risks include, but are not limited to bleeding, blood clots, infection, damage to adjacent organs, and anesthesia. For those patients managed conservatively, the major risk would be not intervening in the presence of a cancer. Although not highly specific, most triage strategies for the management of a pelvic mass have excellent negative predictive values, that is, the ability to predict that a patient does not have cancer. Although not 100%, this can be reassuring to both the clinician and the patient.

5. Prognosis and outcome

"What if" scenarios

What if a patient is not a surgical candidate but still has a suspicious mass?

Aspiration of cyst fluid for definitive diagnosis of an adnexal mass may seem to be a relatively noninvasive approach. Unfortunately, this approach is compromised by poor sensitivity for malignancy at the risk of seeding the abdominal cavity or needle track with malignancy should a malignant mass be aspirated. In general, cyst aspiration is not recommended as a diagnostic approach. Core biopsy of the solid portions of the mass may be helpful if accessible radiologically.

What if the patient is pregnant?

The majority of adnexal masses in pregnancy are benign, given that this is a premenopausal population, with dermoids and corpus luteum cysts being the most common. However, clinical management is based on a balance of radiologic or exam based suspicion versus the possibility of pregnancy loss should intervention be considered. If indicated, the optimal timing of surgery is in the second trimester of pregnancy. Use of the CA-125 marker is compromised by a normal elevation in the first trimester, yielding a higher than normal rate of false positives. Given that many masses resolve during pregnancy, a cautious approach should always be considered and surgical intervention reserved for those masses with a high index of suspicion for malignancy.

6. What is the evidence for specific management and treatment recommendations?

"Management of Adnexal Masses, ACOG Practice Bulletin Number 83, July 2007".

(An excellent resource overall with a good background and review of the topic.)

Levine, D. "Management of Asymptomatic Ovarian and Other Adnexal Cysts Imaged at Ultrasound (Society of Radiologists in Ultrasound Consensus Conference Statement) Ultrasound Quarterly". vol. 26. 2010. pp. 121-31.

(Summary of management recommendations for a variety of adnexal cysts.)

Moore, RG. "Evaluation of the Diagnostic Accuracy of the Risk of Ovarian Malignancy Algorithm in Women With a Pelvic Mass". Obstetrics and Gynecology. vol. 118. 2011. pp. 280-8.

(Description of ROMA use in surgical referral decision making.)

Ueland, FR. "Effectiveness of a Multivariate Index Assay in the Preoperative Assessment of Ovarian Tumors". Obstetrics and Gynecology. vol. 117. 2011. pp. 1289-97.

(Background about OVA-1.)

www.radiologyassistant.nl.

(An excellent resource for imaging descriptions of adnexal masses.)

Im, SS. "Validation of Referral Guidelines for Women with Pelvic Masses". Obstetrics and Gynecology. vol. 105. 2005. pp. 35-41.

(Background for SGO and ACOG referral guidelines.)
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