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An ovarian cyst is a sac filled with liquid or semiliquid material that arises in an ovary.[1] Such cysts can be broadly classified as either functional or neoplastic. Neoplastic ovarian cysts can be either benign or malignant. This slide shows a large benign serous cystadenoma of an ovary at the time of surgery.
It is critical for clinicians to know the different types of ovarian cysts, to apply and be able to interpret appropriate investigations, to be aware of the treatment options available, and to understand when referral to a gynecologic oncologist is indicated.
Image courtesy of C William Helm, MB BChir.
Adnexa uteri ("appendages of the uterus"), or simply adnexa, include the fallopian tubes and ovaries and their supporting vascular supply running through the broad, cardinal, utero-ovarian, round, and infundibulopelvic ligaments. Although an ovarian cyst is an adnexal mass, an adnexal mass is not always an ovarian cyst; the term adnexal mass is often used when the nature of a mass lying between the uterus and either side of the pelvic side wall is not known.[2]
Image courtesy of C William Helm, MB BChir.
During each menstrual cycle, a very well synchronized sequence of events takes place surrounding the maturation and release of an oocyte. The process begins with the development of a cystic swelling up to 2.8 cm in diameter, known as a graafian follicle. At midcycle, after rupture and release of a mature oocyte, this follicle becomes a corpus luteum, a 1.5- to 2-cm structure with a cystic center. If fertilization occurs, the corpus luteum initially enlarges and elaborates progesterone until the placenta takes over that function at about 12 weeks' gestation. If no pregnancy occurs, the corpus luteum generally involutes, but in some cases, it can persist and develop into a functional ovarian cyst (also known as a follicular cyst or cystic follicle).
Image courtesy of Dreamstime | Designua.
The slide shows the adnexal structures on the right side. The ovary and the fallopian tubes are suspended from the pelvic side wall by the infundibulopelvic ligament (also called the suspensory ligament of ovary), which is enveloped by the broad ligament bilaterally. The ovarian vessels course through these ligaments, and vestigial remnants of the wolffian duct system can persist.
Image courtesy of C William Helm, MB BChir.
The slide shows a surgical specimen of a large cyst on the ovary. Many ovarian cysts, both functional and nonfunctional, cause no symptoms, though some patients may present with pelvic pain or an adnexal mass. Not uncommonly, ovarian cysts are found incidentally on an annual gynecologic clinical examination, and their morphologic features are confirmed by means of imaging studies, such as pelvic ultrasonography (US), computed tomography (CT) scanning, or magnetic resonance imaging (MRI).
Which of the following symptoms may be caused by an ovarian cyst?
Image courtesy of C William Helm, MB BChir.
Answer: F. All of the above.
Symptoms that may arise from an ovarian cyst include pain or discomfort in the lower abdomen and pelvis, abdominal distention, fullness, bloating, indigestion, heartburn, early satiety, painful intercourse, irregular periods or abnormal vaginal bleeding, frequency of urination, pressure on the bladder, difficulty with defecation, and leg swelling. Ovarian cysts smaller than 6 cm usually cause no symptoms unless complications, such as twisting, bleeding, or rupture, occur.
Paratubal cysts constitute 10% of all adnexal masses. When the cysts are in proximity to the ovary, they are called paraovarian cysts (shown). Paratubal cysts are usually translucent, unilocular, filled with clear serous fluid, and lined by flattened cuboidal epithelium. They are most commonly remnants of the paramesonephric duct but may also be of mesonephric and mesothelial origin.
Image courtesy of C William Helm, MB BChir.
In the course of evaluating for an ovarian cyst, the abdominopelvic examination may reveal a very large and obvious adnexal mass (shown). Depending on the individual patient, cysts smaller than 4-5 cm may be difficult to palpate on pelvic examination. In symptomatic patients with a body habitus that makes the pelvic examination difficult, imaging is warranted.
Which of the following conditions is least likely to present as an adnexal mass?
Image courtesy of C William Helm, MB BChir.
Answer: C. Pedunculated fibroid of the uterus.
Risk factors for ovarian cyst formation include infertility treatment, tamoxifen use, pregnancy, hypothyroidism, maternal gonadotropins, cigarette smoking, and tubal ligation. The risk factors for ovarian adenocarcinoma include family history, advancing age, white race, infertility, nulliparity, endometriosis, history of breast cancer, BRCA gene mutations, and Lynch II syndrome.
A cystic fibroid mimicking an ovarian cyst is shown.
Image courtesy of C William Helm, MB BChir.
When an adnexal or pelvic mass is palpated on examination or when symptoms are suggestive of an adnexal or pelvic mass, further investigation is indicated. A complete physical examination with emphasis on lymph node enlargement and a careful breast examination are very important. The primary investigations are (a) pelvic US (transvaginal or transabdominal) to determine the site and character of the mass and (b) a pregnancy test (urine or blood) in women of childbearing potential.
Image courtesy of Medscape.
This CT scan shows an abscess in the left ovary. Ovarian cysts can undergo complications—such as torsion, rupture, bleeding, or malignant degeneration—that require surgical intervention. The patient may appear unwell, with marked abdominopelvic pain or fever in association with a cystic adnexal mass.
Image courtesy of Peter Holtz, MD.
Management of an ovarian cyst in pregnancy (shown) depends on the gestational age, the patient's symptoms, the size of the tumor, features suggestive of malignancy, and the risk of complications that can cause an acute abdomen. For asymptomatic patients with ovarian cysts that do not demonstrate any features of malignancy or complications, treatment can be deferred to the postpartum period.
Image courtesy of C William Helm, MB BChir.
Ovarian cysts in pregnant women are frequently identified on routine pregnancy sonograms. The prevalence of adnexal masses in pregnant women is 0.05-3.2% of live births; the most common causes are mature teratomas, paraovarian cysts, and corpus luteum cysts. Cancer antigen 125 (CA125) and other tumor markers are less reliable during pregnancy. Indications for surgery include pain, ovarian cyst torsion, and suspected cancer. Malignancy is diagnosed in only 3.6-6.8% of patients with persistent adnexal masses found on prenatal US[3] (although a nonpersistent mass is not an absolute guarantee of nonmalignancy). In adnexal masses with a low risk of malignancy, the incidence of acute complications (eg, torsion and rupture) is less than 2%; therefore, expectant management is recommended. Surgery for adnexal masses should be delayed until after pregnancy if possible; if surgery is necessary, the best time to perform it is in the second trimester, between weeks 16 and 23. Consultation with maternal-fetal medicine, the neonatal intensive care unit (NICU), and gynecologic oncology is part of comprehensive preoperative preparation and informed consent, especially if surgery is performed after 20 weeks and if malignancy is suspected. No scientific data support a beneficial role for prophylactic tocolysis after adnexal surgery in pregnancy.
Image courtesy of Science Source | Zephyr.
The slide shows a twisted ovarian cyst. Ovarian cysts larger than 4 cm in diameter have a torsion rate of 15%. With ovarian torsion, obstruction of venous flow occurs first, causing ovarian congestion and swelling; compromise of the arterial supply then ensues, leading to ischemia and infarction. Doppler US can assist with diagnosis. The absence of blood flow within an ovary can support the diagnosis of torsion. Treatment options include laparoscopic reversal of torsion and adnexal preservation (in premenopausal women) and salpingo-oophorectomy (in postmenopausal or perimenopausal women). Laparoscopic untwisting may preserve ovarian function in as many as 90% of cases.
Image courtesy of C William Helm, MB BChir.
The slide shows the surgical specimen after a salpingo-oophorectomy secondary to adnexal torsion. The twisting of the pedicle carrying the blood vessels is apparent.
Which of the following is not a complication or symptom of an ovarian cyst?
Image courtesy of C William Helm, MB BChir.
Answer: C. Gastrointestinal bleeding.
The best ancillary test for visualizing the pelvic and adnexal structures is transvaginal US. High-frequency, gray-scale transvaginal US can produce high-resolution images of an adnexal mass that approximate its gross anatomic appearance.
The sonograms in the slide show a surgically proven case of a ruptured left hemorrhagic corpus luteal cyst with hemoperitoneum. Ovarian cyst rupture is common with corpus luteum cysts. It involves the right ovary in two thirds of cases and usually occurs between days 20 and 26 of the woman's menstrual cycle. In ovarian cyst rupture, US may demonstrate free fluid in the pouch of Douglas.
Image courtesy of Radiopaedia.org.
The transvaginal sonogram in the slide shows a simple ovarian cyst. Ovarian cysts identified on US can be divided into two main types: simple and complex. On US, a simple ovarian cyst has a rounded shape and a uniformly thin wall. It is unilocular, hypoechoic or anechoic, and usually 2.5-15 cm in diameter. Posterior acoustic enhancement may be visible deep to the fluid-filled cyst. Simple cysts are likely benign, including follicular cysts, luteal cysts, inclusion cysts, and serous cystadenomas.[4] Simple cysts up to 10 cm in diameter are almost universally benign and may be safely followed without intervention, even in postmenopausal patients.
Image courtesy of Patrick Yeung Jr, MD.
Complex cysts are characterized by solid components (papillary projections), thick walls, thick septations, multiple compartments (multilocularity), and increased vascularity within the cyst. Malignant cysts usually fall within this category, as do many benign neoplastic cysts.
This sonogram depicts a large, complex cystic mass with blood flow within the septations. Complex cysts detected on imaging are worrisome for malignancy. Although the diagnosis of a cancer can only be made with pathologic examination of tissue, the findings from the history, examination, and imaging play a role in determining whether a cyst in the ovary is likely to be malignant. US can easily identify the presence of a cyst and help to confirm that it is arising from an ovary. It can also define structural characteristics of a cyst that can help with determining the etiology and establishing whether the cyst is benign or cancerous.
Image courtesy of Medscape | Patrick O'Kane, MD.
Findings on US that are suspicious for malignancy include the presence of a complex cyst, bilaterality, and ascites.
The transvaginal sonogram seen here shows a complex ovarian cyst with a solid area (papillations) arising from the posterior wall of the cyst. Such a cyst should be considered malignant until proven otherwise. In complex, multiloculated cysts, the risk of malignancy is approximately 36%.[5]
Image courtesy of C William Helm, MB BChir.
The slide shows the inside surface of a complex ovarian cyst with cancer confined to the ovary (stage I). If cancer is diagnosed, regional or distant spread may be present in as many as 70% of cases; only 25% of new cases will be limited to stage I disease.[5] Mortality associated with malignant ovarian carcinoma is related to the stage at the time of diagnosis, and patients with this carcinoma tend to present late in the course of the disease. The overall relative 5-year survival rate for ovarian cancer, according to the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, is 46.2%.[6]
Image courtesy of C William Helm, MB BChir.
The transvaginal sonogram seen here shows an endometrioma with characteristic homogeneous, low-level echoes. Hemorrhagic cysts, endometriomas, and dermoid cysts (or mature cystic teratomas) tend to have characteristic features on US that may help to differentiate them from malignant complex cysts. However, US may not be helpful for differentiating hydrosalpinx, paraovarian cysts, and tubal cysts from ovarian cysts.
Image courtesy of Patrick Yeung Jr, MD.
The transvaginal sonogram in this slide shows a polycystic ovary with multiple hypoechoic follicles. Polycystic ovaries typically exhibit three characteristics on US: bilateral enlarged ovaries, multiple small follicles, and increased stromal echogenicity. The follicles are small (0.5-0.8 cm), and no dominant follicle is present. Characteristically, the follicles are peripherally located in the cortex; however, they can occur anywhere in the ovarian parenchyma. The diagnosis of polycystic ovaries should be reserved for patients with at least five of these follicles in each ovary. Typically, the ovaries are hypoechoic in relation to the surrounding pelvic fat and myometrium. Polycystic ovaries often display increased echogenicity.[7] By itself, the presence of ovaries with a polycystic appearance on US is not sufficient to establish the diagnosis of polycystic ovarian syndrome.
Image courtesy of Patrick Yeung Jr, MD.
Morphologic characteristics of ovarian cysts can also be differentiated by means of CT scanning, which is necessary for very large cysts that will not fit in the field of view of an ultrasonographic device. After a thorough transvaginal ultrasonographic examination is performed, however, additional imaging with CT scanning or MRI is of limited value. Currently, the best use of CT scanning is not for the detection and characterization of pelvic masses but for the evaluation of the abdomen for metastasis (omental metastasis, peritoneal implants, pelvic or periaortic lymph node enlargement, hepatic metastasis, or obstructive uropathy) when a cancer is suspected. The abdominal CT scan here shows a serous cystadenoma.
Which of the following statements about cysts in postmenopausal women is not correct?
Image courtesy of C William Helm, MB BChir.
Answer: D. A complex cyst may be followed for several weeks if it is smaller than 10 cm, the patient is asymptomatic, and CA125 is normal.
In postmenopausal patients, the presence of an ovarian cyst prompts measurement of the CA125 level. The presence of a complex cyst or an increased CA125 level is highly suggestive of malignancy in this age group.[8,9] With the exception of simple cysts,[10] most pelvic masses in postmenopausal women will warrant surgical intervention. It must also be kept in mind that the ovary is a site for metastases from uterine, colorectal, gastric, and breast cancers. The image shows a 3.1-cm simple cyst.
Image courtesy of Patrick Yeung Jr, MD.
In premenopausal patients, simple ovarian cysts often need not be treated. Treatment of patients in this age group is influenced by the presence of abdominopelvic symptoms. Acutely symptomatic patients usually have a diagnosis that necessitates immediate treatment, whether medical or surgical; ectopic pregnancy, tubo-ovarian abscess, and adnexal torsion or rupture are the most common of these diagnoses. In patients with subacute or chronic symptoms, an ovarian mass is rarely malignant; endometriomas, fibromas, and dermoid cysts are the most common lesions.
Current evidence does not support the use of oral contraceptives to treat existing functional or benign ovarian cysts;[11] research into this issue has failed to prove that such therapy leads to increased or faster resolution of these lesions.
The simple cyst shown here has a smooth internal surface, without signs of cancer.
Image courtesy of C William Helm, MB BChir.
Secondary investigations for ovarian cysts include CT scanning, MRI, and measurement of CA125, beta human chorionic gonadotropin (β-hCG; associated with choriocarcinoma), alpha-fetoprotein (AFP; associated with endodermal sinus tumor), lactate dehydrogenase (LDH; associated with dysgerminoma), and human epididymis protein 4 (HE4; associated with ovarian cancer). It should be noted that CA125 is not specific for ovarian cancer and that levels are elevated in many benign and malignant conditions.
Tertiary investigation includes surgical evaluation (diagnostic laparoscopy or exploratory laparotomy). Aspiration of cyst fluid is performed principally for CT scan-guided drainage of suspected pelvic abscesses. Other types of cysts, particularly complex cysts, are not aspirated, because of the risk of spreading cancer cells and upstaging the tumor.
The slide shows a ruptured ovarian cyst. The rupture led to hemorrhage, and the treatment was surgical removal of the ovary. The roles of surgery in the treatment of ovarian cysts are as follows:
Removal of a cyst from an ovary often leads to rupture; cysts that are potentially cancerous should be removed intact, if possible.
Image courtesy of C William Helm, MB BChir.
Several methods have been suggested for predicting preoperatively whether an adnexal mass is malignant, although none are 100% accurate. The Risk of Malignancy Index (shown) is a product of the US score, the menopausal status, and the serum CA125 level.[12,13] Patients with scores of 250 or higher should be considered for referral to a specialist. The Multivariate Index Assay is another method reported to improve predictability of ovarian cancer in women with pelvic masses.[14,15] It is based on five biomarkers: transthyretin, apolipoprotein, beta2 microglobulin, transferrin, and CA125 II. The combination of serum HE4 and CA125 has been reported to increase the accuracy of prediction of malignancy of an adnexal mass.[16-19] If there is any doubt as to whether an ovarian cyst is malignant, the patient should be referred to a gynecologic oncologist.
Image courtesy of Wikimedia Commons | Armin Kübelbeck.
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