DefinitionOvarian cysts, also known as ovarian masses or adnexal masses, are frequently found incidentally in asymptomatic women. Ovarian cysts can be physiologic (having to do with ovulation) or neoplastic and can be benign, borderline (low malignant potential), or malignant. Ovarian cysts are sometimes found in the course of evaluating women for pelvic pain though the cysts may or may not be the cause of the pain. Show
Back to Top EpidemiologyEstimates of the prevalence of ovarian cysts vary widely, with most authors reporting between 8% and 18% of both premenopausal and postmenopausal women having ovarian cysts. Most post-menopausal cysts persist for years.1 In the United States, approximately 5% to 10% of women undergo surgical exploration for ovarian cysts in their lifetime though only 13% to 21% of these cysts are malignant.2 Presurgical evaluation of ovarian cysts is critical to prevent unnecessary surgical intervention while still detecting potential malignancy. For the vast majority of women, ovarian cysts are not precancerous lesions and do not increase the risk of developing ovarian cancer later in life. Removal of benign cysts does not decrease future mortality from ovarian cancer.1,3-5 Back to Top PathophysiologyProvided below is a brief description of the pathophysiology of various types of physiologic and neoplastic ovarian cysts and the potential complications that may arise. Physiologic/Functional CystsDuring normal ovulation, a follicle matures and then ruptures, releasing an oocyte. After ovulation, the corpus luteum forms and subsequently involutes. When the follicle fails to rupture and continues to grow, a follicular cyst occurs. When the corpus luteum fails to involute and continues to grow, a corpus luteum cyst occurs. Both types of cysts are considered physiologic or functional and neither have any malignant potential. Either type of cyst can become a hemorrhagic cyst (see below). Hemorrhagic CystsThe granulosa layer of the ovary remains avascular until the time of ovulation. After ovulation occurs, the granulosa layer quickly becomes vascularized by thin-walled vessels, which rupture easily, giving rise to a hemorrhagic cyst.6 Dermoids (Mature Cystic Teratomas)Dermoid cysts contain mature tissue of ectodermal (eg, skin, hair), mesodermal (eg, muscle, urinary), and endodermal (eg, gastrointestinal, lung) origin.7 Dermoid cysts are almost always benign but have the potential to rupture, spilling sebum, or torse. EndometriomaEndometrioma is a type of cyst that is filled with menstrual blood and endometrial tissue. Endometrioma cysts arise either via retrograde menstruation from the uterus or bleeding from an endometriotic implant itself. Ovarian MalignancyStudies suggest that some seemingly ovarian serous carcinomas actually originate in the fallopian tubes and then spread to the ovary. These tubal lesions have also been found to spread to the peritoneum, leading to an apparent peritoneal carcinoma. Germ cell and stromal tumors do arise from the ovary itself. Complications
Back to Top Signs and SymptomsMost women with benign or malignant ovarian cysts are asymptomatic and the cysts are found incidentally. Among women with symptoms, pelvic or lower-abdominal pressure or pain are the most common symptoms. Acute pain related to ovarian cysts can occur with ovarian torsion, hemorrhage into the cyst, cyst rupture with or without intra-abdominal hemorrhage, ectopic pregnancy, and pelvic inflammatory disease with tubo-ovarian abscess.8 Vague symptoms such as urinary urgency or frequency, abdominal distention or bloating, and difficulty eating or early satiety have also been reported.9 The positive predictive value of this symptom constellation is only about 1%; however, the usefulness increases if symptoms arose recently (within the past year) and occur more than 12 days a month.10 Back to Top DiagnosisThe differential diagnosis of benign ovarian cysts includes:
The diagnosis of an ovarian cyst is most often made based on imaging rather than by physical examination, laboratory testing, or diagnostic procedures. UltrasoundUltrasonography is considered the gold standard for the assessment of ovarian cysts. Transvaginal sonography is preferred, as the probe proximity to the ovary can result in superior images. If transvaginal sonography is not available or not tolerated by the patient, transabdominal sonography through a full bladder or transperineal sonography in virginal or atrophic women can still provide helpful, albeit limited, information. In some cases, ultrasound can specifically diagnose the type of ovarian cyst, especially if certain characteristic findings are present (Box 1). Figures 1– 5 illustrate and describe characteristic findings seen with simple cysts, hemorrhagic corpus luteum cysts, dermoid cysts, endometriomas, and malignant cysts.8 Box 1: Characteristics of Simple and Malignant Cysts
Identifying certain cyst characteristics is especially important in differentiating benign from malignant processes. The ten "Simple Rules" are five ultrasound features indicative of benign cysts (B-features) and five ultrasound features indicative of a malignant cysts (M-features) based on the presence of tumor morphology, degree of vascularity, and ascites (Table 1).11 Table 1: "Simple Rules" Differentiating Benign and Malignant Cysts
a Most predictive feature. b Least predictive feature. Data from Timmerman D, Van Calster B, Testa A, et al. Predicting the risk of malignancy in adnexal masses based on the Simple Rules from the International Ovarian Tumor Analysis group. Am J Obstet Gynecol 2016; 214:424–437. Magnetic Resonance ImagingMagnetic resonance imaging (MRI) is a valuable tool when ultrasound is inconclusive or limited. The advantages of MRI are that it is very accurate and it provides additional information on the composition of soft-tissue tumors.8 On the other hand, MRI is more expensive, is usually less available, and is more inconvenient for the patient than ultrasound. MRI for the evaluation of ovarian cysts is usually ordered with contrast, unless contraindicated.8 In one study of MRI as second-line imaging for indeterminate cysts, contrast-enhanced MRI contributed to a greater change in the probability of ovarian cancer compared with computed tomography (CT), Doppler ultrasound, or MRI without contrast.12 This may result in a reduction in unnecessary surgeries and in an increase in proper referrals in cases of suspected malignancy. Computed TomographyComputed tomography (CT) is usually not used in the evaluation of ovarian cysts. CT offers poor discrimination of soft tissue and exposes the patient to more radiation than does ultrasound or MRI. The utility of CT is primarily in the preoperative staging of a suspected ovarian cancer.13 Cysts discovered via CT scan should be further evaluated using ultrasonography. Diagnostic ProceduresIt is almost never appropriate to aspirate an ovarian cyst for diagnostic purposes. False negative results are common and leakage of cyst contents into the peritoneal cavity potentially increases the stage of any cancer found, decreasing patient survival. Back to Top ManagementAppropriate management of patients with an ovarian cyst depends on the presence of symptoms, likelihood of torsion or rupture, and level of concern for malignancy. Symptomatic CystsThe differential diagnosis for pain in women with ovarian cysts include tubo-ovarian abscess, ruptured ectopic, ruptured hemorrhagic cyst, and ovarian torsion.8 If the patient with pain is at low risk of a surgical emergency, pain medication and outpatient management is appropriate. If pain persists, refer the patient to a gynecologist. For a patient who appears toxic or is in shock, an immediate surgical consultation with a gynecologist is warranted. For patients with symptomatic cysts that are concerning for cancer, consult a gynecologic oncologists directly. Simple CystsManagement of patients with simple cysts should follow the algorithm shown in Figure 6. Cysts with a High Likelihood of MalignancyWomen with ovarian cysts with a high likelihood of malignancy should be referred directly to a gynecologic oncologist. High likelihood of malignancy exists if malignant features are found on ultrasound, in women with a personal history or a first-degree relative with history of ovarian or breast cancer, or if cancer antigen 125 (CA 125) is >35 (postmenopausal women) or CA 125 >200 (premenopausal women) (Figure 7). Direct referral to and treatment by gynecologic oncologists has been shown to improve survival rates in women with ovarian cancer.14-16 Cysts with an Indeterminate Likelihood of MalignancyFor women with cysts with an intermediate likelihood of malignancy, further workup is warranted. The most cost-effective test is a second ultrasound and a second opinion at a tertiary center. Obtaining the CA 125 level can be helpful in this instance (Figure 7). Cysts with an Unclear Likelihood of Malignancy but Likely BenignFor women with cysts with an unclear likelihood of malignancy but most likely benign, repeat ultrasound in 6 to 12 weeks is warranted.8 There are no official guidelines as to when to stop serial imaging, but one or two ultrasounds to confirm size and morphologic stability has been suggested.17 Of course, once a lesion has resolved, there is no need for further imaging. Back to Top Prevention and ScreeningPreventionOral contraceptives may prevent new functional cysts from forming.18-19 Oral contraceptives do not, however, hasten the resolution of preexisting cysts. Some practitioners will, nevertheless, prescribe oral contraceptives in an attempt to prevent new cysts from confusing the picture. Oral contraceptives are also protective against ovarian cancer.20 Bilateral oophorectomy protects against ovarian and breast cancer but is associated with an increase in the all-cause mortality rate.21 Current research suggests that removal of the fallopian tubes is protective against ovarian cancer.22 ScreeningScreening women with an average risk for ovarian cancer is not recommended.3,23 The incidence of ovarian cancer is too low, ultrasonography and CA 125 testing are too nonspecific, and the biology of ovarian cancer does not lend itself to screening. In one recent large study (N = 78,216), yearly screening with CA 125 and ultrasound did not decrease the mortality rate from ovarian cancer, and the surgical evaluation of false-positive screens was associated with complications.5 Back to Top Special PopulationsPregnancyOvarian cysts in pregnancy are usually benign. Benign cystic teratomas (also called dermoid cysts) are the most common ovarian tumor during pregnancy, accounting for one-third of all benign ovarian tumors in pregnancy. The second most common benign ovarian cyst is a cystadenoma. In caring for pregnant women with ovarian cysts, a multidisciplinary approach and referral to a perinatologist and gynecologic oncologist is advised. Neonates and Prepubertal ChildrenOvarian cysts in the neonate are exceedingly rare. It is estimated that 5% of all abdominal masses in the first month of life are ovarian cysts. While there are no precise guidelines for the monitoring and management of neonatal ovarian cysts, it is generally agreed that cysts >2 cm are considered pathologic. The majority of neonatal ovarian cysts are benign and self-limiting. Ovarian malignancy becomes more common in the second decade of life than in the neonatal period. In one small study, approximately 33% of adnexal masses were malignant in children >8 years whereas 2.9% of adnexal masses were malignant in children <8 years.24 Women with a History of Breast CancerWomen diagnosed with ovarian cysts with a personal or family history of breast or ovarian cancer in a first degree relative should be referred directly to a gynecologic oncologist. Polycystic Ovarian SyndromeThe finding of multiple small ( <1 cm) cysts in both ovaries ("string of pearls" appearance) on ultrasonography is indicative of polycystic ovarian syndrome, a condition unrelated to other ovarian cyst conditions. The "string of pearls" appearing cysts are a component of a multi-system syndrome, which usually also includes irregular ovulation and aspects of metabolic syndrome. Back to Top Summary
AcknowledgementsThank you very much to Mina Tirabassi, RDMS, for the ultrasound images. References
Back to Top DisclosuresElisa Ross, MD; nothing to disclose. Chelsea Fortin, MD; nothing to disclose. Can you tell if an ovarian cyst is cancerous from an ultrasound?Vaginal ultrasound can help to show whether any cysts on your ovaries contain cancer or not. If a cyst has any solid areas it is more likely to be cancer. Sometimes, in women who are past their menopause, the ovaries do not show up on an ultrasound. This means that the ovaries are small and not likely to be cancerous.
How can you tell the difference between ovarian cyst and ovarian cancer?Ovarian cysts are sacs or pockets of regular tissues or cells, and are usually filled with fluid, while ovarian tumors are solid masses of cancer cells. Most ovarian cysts come and go with menstrual cycles, while ovarian tumors will not go away on their own, and will require treatment.
What does an ovary with cancer look like on an ultrasound?Three-dimensional, color Doppler ultrasonogram shows a cystic mass containing a vascular papillary excrescence; this is indicative of ovarian cancer. The ultrasonographic finding that is most indicative of ovarian cancer is papillary excrescence, which is present in more than 50% of ovarian malignancies.
Can ovarian cancer look like a cyst?The signs of ovarian cancer are similar to those of cysts, often involving: Abdominal bloating and pressure. A frequent urge to urinate. Lower abdominal or pelvic pain.
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