The normal functioning ovary produces a follicular cyst 6-7 times each year. In most cases, these functional masses are self-limiting and resolve within the duration of a normal menstrual cycle. In rare situations, they persist longer or become enlarged. At this point, they represent a pathological condition.
Adnexal masses present a diagnostic dilemma; the differential diagnosis is extensive, with most masses representing benign processes.1, 2, 3 However, without histopathologic tissue diagnosis, a definitive diagnosis is generally precluded. Physicians must evaluate the likelihood of a pathologic process using clinical and radiologic information and balance the risk of surgical intervention for a benign versus malignant process.
Since ovaries produce physiologic cysts in menstruating women, the likelihood of a benign process is higher. In contrast, the presence of an adnexal mass in prepubertal girls and postmenopausal women heightens the risk of a pathologic etiology.
For related information, see Medscape’s Women’s Sexual Health Resource Center.
History of the Procedure
In the past, physicians relied on the findings of a pelvic examination to diagnose an adnexal mass. With the introduction of imaging modalities including transabdominal or vaginal ultrasonography, Doppler color scans, and MRI scans, more characterization of the internal structure of the mass (ie wall complexity, mass contents) is possible.4, 5, 6, 7 Although not definitive, these findings can help determine whether a mass appears more consistent with a physiologic cyst or neoplastic process.
The following masses pose the greatest concern:
Those that have a complex internal structure
Those that have solid components
Those that are associated with pain
Masses in prepubescent or postmenopausal women
Large cysts (A variety of cut off sizes have been proposed. In some institutions, unilocular cysts up to 10 cm have been followed conservatively, even in postmenopausal women.7 However, complex cysts in this same group of patients generally heightens suspicion, regardless of size.)
In menstruating women, those who persist beyond the length of a normal menstrual cycle without typical characteristics of a benign process such as a hemorrhagic cyst
Determining the true frequency of adnexal masses is impossible because most adnexal cysts develop and resolve without clinical detection. When assessing the clinical significance of an adnexal mass, considering several age groups is important.
In girls younger than 9 years, 80% of ovarian masses are malignant and are generally germ cell tumors.8, 9 During adolescence, 50% of adnexal neoplasms are adult cystic teratomas. Women with gonads that contain a Y chromosome have a 25% chance of developing a malignant neoplasm. Endometriosis is uncommon in adolescent women but may be present in as many as 50% of those who present with a painful mass. In sexually active adolescents, one must always consider a tubo-ovarian abscess as the cause of an adnexal mass.10, 11
In women of reproductive age who have had adnexal masses removed surgically, most are benign cysts or masses. Ten percent of masses are malignant12; many tumors in patients younger than 30 years are of low malignant potential. Thirty-three percent are adult cystic teratomas, and 25% are endometriomas. The rest are serous or mucinous cystadenomas or functional cysts.
Historically, postmenopausal women with clinically detectable ovaries were felt to be at great risk of having a malignant neoplasm. With the introduction of radiologic testing, many smaller, simple cystic masses have been identified; therefore, the risk of malignancy may be only 20-30%. The differential includes benign cysts, metastatic versus primary ovarian malignancies, tubal cysts and neoplasms such as paratubal cysts, hydrosalpinx, or rarely fallopian tube cancer. Radiologic testing allows the architecture of the mass to be evaluated, which decreases the need to operate on benign masses in this age group.
In all age groups, the physician must also consider the possibility of uterine masses or structural deformities. Pregnancy-related adnexal masses, including ectopic pregnancy, theca lutein cysts, corpus luteum cysts, and luteomas, must be considered in all premenopausal women.13, 14
The pathophysiology is not well understood for most adnexal masses; however, some theories have been proposed. Functional cysts may be the result of variation in normal follicle formation. Adult cystic teratomas (dermoid) may be the result of an abnormal germ cell. Endometriomas are thought to result from retrograde menstruation or coelomic metaplasia. The exact cause of epithelial neoplasms is unknown, but recent studies have suggested a complex series of molecular genetic changes is involved.
The clinical presentation of an adnexal mass can be variable, but patients are often asymptomatic, presenting with masses that are found (1) at the time of a pelvic examination, (2) at the time of a radiologic examination for another diagnosis, or (3) at the time of a surgical procedure. Women who have symptoms may note urinary frequency, pelvic or abdominal pressure, and bowel habit changes due to the mass effect on these organs. Girls younger than 10 years frequently present with pain, as do older women who have infected masses or endometriosis. Adnexal torsion often presents with acute abdominal pain, requiring urgent surgical intervention.
Many adnexal masses present as asymptomatic, small, and simple cystic masses. Most of these resolve spontaneously; therefore, care must be taken to not overreact to such a finding. Surgeons who rush these women into surgery often create more pathology than they cure. Any surgery performed on adnexal structures can result in impaired fertility.
On the other hand, these same asymptomatic masses can be early ovarian cancers that require immediate attention. The use of radiologic testing often helps determine which women require attention (see Imaging Studies). The use of cancer antigen 125 (CA-125) can be used in combination with radiologic testing to stratify the risk of adnexal masses. However, in the general population, the use of CA-125 to screen for the presence of cancer should be discouraged.15 A large Swedish study has shown that approximately 50% of women with stage I ovarian cancer have a normal CA-125 test value. In addition, a high false-positive rate can be caused by pregnancy, endometriosis, cirrhosis, and pelvic or other intra-abdominal infections.16, 17, 18
The term adnexa is derived from the pleural form of the Latin word meaning “appendage.” The adnexa of the uterus include the ovaries, fallopian tubes, and structures of the broad ligament. Most frequently, adnexal masses refer to ovarian masses or cysts; however, paratubal cysts, hydrosalpinx, and other nonovarian masses are also included within the broader definition of adnexal masses.
Several other anatomical structures are important to identify, both for the evaluation of other sources of masses within the pelvis and during surgical procedures to prevent damage to nearby organs and structures. The uterus is central to both adnexal regions and can be the source of a pelvic mass. For instance, exophytic, pedunculated fibroids can mimic adnexal masses on preoperative imaging. The rectum and bladder are located posterior and anterior to the adnexal regions. Both can be the source of pelvic masses, although this is less frequent. In addition, they must be protected from injury when adnexal surgery is performed. The ureters are located near the ovarian blood supply and can be damaged easily during adnexal surgery. Many of the pathologic processes associated with adnexal masses can alter the location of the ureters, increasing the chance of damage.
Many adnexal masses present as asymptomatic, small, simple cystic masses, most of which can resolve spontaneously. Considering nonsurgical management and follow-up in patients with low-risk adnexal masses is important to avoid unnecessary procedures, particularly as procedures performed on adnexal structures may result in impaired fertility.
Many adnexal masses can be removed using laparoscopic techniques and are associated with little postoperative complexity.19 However, in those women with significant preexisting medical problems and/or cancer, major postoperative problems can be encountered and preoperative evaluation is important to assess clearance for surgery (see Postoperative Details and Complications).