Tuesday, September 28, 2021

Adnexal Masses in Pregnancy Case File

Posted By: Medical Group - 9/28/2021 Post Author : Medical Group Post Date : Tuesday, September 28, 2021 Post Time : 9/28/2021
Adnexal Masses in Pregnancy Case File
Eugene C. Toy, MD, Edward Yeomans, MD, Linda Fonseca, MD, Joseph M. Ernest, MD

Case 42
A 28-year-old woman, G2P1001, presented for prenatal care at 16 weeks’ gestation. Her only complaint was excessive weight gain of 25 lb to this point in pregnancy. The patient had no other medical problems other than allergic rhinitis. Her obstetrical history was significant for a prior term vaginal delivery without complications.

On physical examination her vitals were as follows: BP 98/65 mm Hg, HR 95 bpm, BMI = 28 kg/mm2. The only finding on examination was that the maternal abdomen was distended with a positive fluid wave and the uterus was difficult to palpate abdominally. There were no other significant findings. Given this examination finding, you question the patient further and she denies early satiety, bloating, nausea, vomiting, and fever/chills.

An ultrasound in the office showed a 16 weeks, 2 days intrauterine pregnancy. The maternal abdominal cavity showed a large amount of ascites. Ovaries could not be visualized. Magnetic resonance imaging (MRI) of the abdomen and pelvis was ordered and it revealed a large cystic mass extending from the pelvis to the abdominal cavity measuring 30 × 15 cm likely arising from the left ovary. The cyst was without wall thickening, septations, or projections. There was no apparent adenopathy or free fluid. The right ovary appeared normal. You call the patient to discuss the results of her MRI.

➤ What is your next step in the management?
➤ What is in your differential diagnosis of an adnexal mass in pregnancy?

Adnexal Masses in Pregnancy

Summary: A 28-year-old G2P1001 at 16 2/7 weeks’ gestation with an incidental finding of a large pelvic mass and ascites.

Next step: The patient should be counseled that although most adnexal masses during pregnancy are benign and resolve, this particular mass is more concerning due its large size and the presence of ascites. Surgical management is the best option in this particular situation.

Differential diagnosis: Common etiologies of adnexal masses in pregnancy include functional cysts (corpus luteum, hemorrhagic, simple) as well as dermoids, endometriomas, and paraovarian cysts. Borderline tumors or malignancy are less likely in general but are strong considerations in this case.

  1. Describe the characteristics of adnexal masses that are physiologic versus neoplasms.
  2. Describe the diagnostic strategy for adnexal masses in pregnancy.
  3. Describe the treatment of adnexal masses in pregnancy.

There are several factors that must be considered when recommending surgery versus expectant management in a gravid patient with an adnexal mass. Sonographic characteristics, size, symptoms, persistence, and gestational age are all important considerations.

In general, adnexal masses with size > 5 cm, complex consistency (cystic and solid), presence of excrescences, mural nodules, septations, wall thickness, and ascites raise the concern for malignancy. With few exceptions, these masses should be excised regardless of concurrent pregnancy. Waiting until the fetus is term would generally not be considered appropriate with a lesion of this size because a potentially malignant lesion would have time to spread, thereby affecting the mother’s overall survival. In general, the risk of malignancy of persistent masses in pregnancy is low. If surgical intervention is being considered, it should be planned for after 16 weeks’ of gestation for two reasons. First, most adnexal masses are functional cysts and resolve by 16 weeks’ gestation. Secondly, most spontaneous abortions occur in the first trimester and therefore waiting until later in pregnancy may help to avoid unnecessary surgery during pregnancy.

The first step in management is to evaluate the mass via imaging studies starting with gynecological sonogram and proceeding to a computed tomography scan (CT-scan) or an MRI. The most appropriate management for this particular patient given the size of the mass would be an exploratory laparotomy with an attempt to preserve the ovary. Additionally, the patient should be counseled that a staging procedure by a gynecologic oncologist may also be indicated based on intraoperative findings. Had the mass been smaller, perhaps a laparoscopic approach could have been initiated. The timing of the procedure would ideally occur at 16 to 18 weeks of gestation when most functional cysts have already resolved. Whether observation or antepartum surgical intervention is chosen, the patient should be properly counseled regarding the risks, benefits, and alternatives of the proposed management. 

With expectant management, one of the more common complications in pregnant patients with adnexal masses is pain especially in those with larger masses. Pain can also be due to torsion which has a variable reported rate of less than 1% to 22% of cases. Rupture of adnexal masses in pregnancy is less common, occurring in less than 9% of cases. Another potential complication of adnexal masses in pregnancy is obstruction of labor which may occur in 2% to 17% of cases1 (Level III). Much lower antepartum complication rates (< 2%) have been reported with expectant management in other studies2,3,4 (Level II-2, Level III). Even with emergent surgery due to torsion or other acute complications, adverse pregnancy outcome is significantly low4 (Level III). 

The risks of surgery during pregnancy include miscarriage and preterm birth, however, these risks are minimized if surgery is performed in the second trimester. Both laparoscopy and laparotomy, when performed by skilled operators, have been shown to have similar pregnancy outcomes5 (Level III). That being said, the risks of observation need to be balanced against the risks of surgical intervention. In this particular patient, the concern is twofold—the presence of a large adnexal mass and ascites, both of which are concerning for an ovarian neoplasm or malignancy.

Adnexal Masses in Pregnancy
The finding of an incidental adnexal mass in pregnancy has become more common with the routine use of ultrasound in prenatal care. For this reason, many incidental masses will be detected by ultrasound in the first or second trimester of pregnancy. Approximately 1% to 4% of pregnant women are diagnosed with an adnexal mass2,6 (Level II-2). The majority of these masses are corpus luteum or other functional cysts that usually resolve by 16 weeks of gestation. Some adnexal masses persist and 1% to 8% of these masses represent malignant tumors7,8,9-11 (Level II-3, Level II-2, Level III). Size is the best indicator of whether the mass requires surgical intervention. Slightly less than 100% of masses smaller than 5 cm in diameter will resolve spontaneously. Larger cysts have increased risk of torsion, rupture, and labor obstruction, therefore close monitoring and often surgery are necessary12 (Level III).

Common adnexal lesions associated with pregnancy include simple cysts, hemorrhagic cysts, and hyperstimulated ovaries in patients who have undergone assisted fertility. Uncommon adnexal lesions specific to pregnancy include heterotopic pregnancy, hyperreactio luteinalis, theca lutein cysts with moles, and luteinomas. Some adnexal entities are found incidentally, such as teratomas, endometriomas, leiomyomas, hydrosalpinx, cystadenomas, and cystadenocarcinomas (see Table 42–1 for differential diagnosis).

Improvements in ultrasound technology have increased the ability to better characterize adnexal masses. The use of color Doppler imaging has been shown to significantly improve the ability to distinguish benign from malignant masses13 (Level III). The sensitivity of ultrasound in distinguishing


• Simple cysts
• Corpus luteum
• Hemorrhagic cysts
• Endometriomas
• Leiomyomas
• Paraovarian cysts
• Hydrosalpinx
• Tubo-ovarian abscess
Unique to pregnancy
• Hyperstimulated ovaries
• Hyperreactio luteinalis
• Theca lutein cysts
• Luteomas
• Heterotopic pregnancy
• Teratomas
• Cystadenomas
• Cystadenocarcinomas
• Acute appendicitis
• Irritable bowel disease
• Adhesive disease
benign from malignant disease is 96.8% with specificity of 77%. Although the diagnosis of most adnexal pathologic conditions can be made on the basis of sonographic appearance alone, MRI may help when the sonographic appearance is not specific or the mass is unable to be adequately imaged. Familiarity with these clinicopathologic and imaging features is important for diagnosis and treatment12 (Level III).

Most adnexal masses detected by sonography during pregnancy are simple cysts or hemorrhagic corpus luteum cysts. Simple cysts are unilocular and anechoic and have a smooth, thin wall. The prevalence of simple cysts at 8 to 10 weeks is 5.3% dropping to 1.5% by 14 weeks gestation. Follicular cysts are simple cysts that develop in response to monthly cyclical hormonal change and are less than 2 cm in size5 (Level III). Corpus luteum cysts support pregnancy by maintaining progesterone levels. These cysts enlarge during the first trimester, regress by the 12th week of gestation, and disappear later on in the pregnancy12 (Level III). Sonographic appearance varies from simple to complex with internal debris and thick walls. The corpus luteum is typically surrounded by a circumferential rim of color Doppler flow with a low-resistance Doppler pattern often referred to as the “ring of fire.” These cysts are prone to rupture and hemorrhage.

Hemorrhagic cysts can have a variety of sonographic appearances due to the changing appearance of the blood clot12 (Level III). Hemorrhagic cysts appear as predominantly anechoic masses that contain hypoechoic material within them12 (Level III). Acutely hemorrhagic cysts can appear as echogenic masses with internal echoes more hyperechoic than surrounding normal ovarian parenchyma in a “fishnet” or reticular pattern. The appearance over time may evolve to include a solid component representing a retracting blood clot with low-level echoes. Color Doppler interrogation will show no vascularity within the solid component.

The mature cystic teratoma is the most common benign ovarian neoplasm to be diagnosed in pregnancy. Teratomas show a complex echo pattern on ultrasound due to the presence of fat, solid components, and calcified material12 (Level III). Sonographic appearances include the presence of a hyperechoic nodules, acoustic shadowing due to dense calcifications and multiple interdigitating lines representing hair floating in sebum12 (Level III). Teratomas my be pedunculated and are prone to undergoing torsion and rupture, leading to peritonitis12 (Level III). The most common sonographic appearance of endometriomas is that of diffuse homogenous low-level internal echoes although the appearance may vary from a cystic lesion to a solid mass depending on the stage of degradation of blood products5 (Level III).

Lesions specific to pregnancy include hyperstimulated ovaries. Ovarian hyperstimulation syndrome appears as markedly enlarged ovaries (> 5 cm) containing multiple, large, peripherally located, thin-walled cysts that sometimes exude fluid from hemorrhage or ascites. They usually regress later in pregnancy or after delivery12 (Level III). Hyperreactio luteinalis are similar in appearance to hyperstimulated ovaries but are seen in patients who have not undergone ovulation induction. They are thought to result from hypersensitivity of the ovary to circulating human chorionic gonadotropin (hCG) which may or may not be high12 (Level III). These can commonly be mistaken for an ovarian neoplasm, however, MRI can be useful in distinguishing it from, or decreasing the likelihood of, a neoplasm12 (Level III). Theca lutein cysts are reported with complete hydatiform moles 14% to 30% of the time which are stimulated by high levels of circulating hCG. They appear as anechoic, multiloculated, ovarian cysts12 (Level III). The presence of a uterus filled with small cysts is the key to the diagnosis. Partial molar pregnancy is not likely to have theca lutein cysts. Luteomas are rare solid lesions that occur unique to pregnancy. Fewer than 200 cases of luteoma have been reported in the literature.14. Luteomas cause maternal virilization in 25% to 30% of cases and carry a 50% risk of virilizing a female fetus12 (Level III). On sonography, they appear as heterogeneous solid masses, predominantly hypoechoic compared with normal ovarian tissue, with thick walls and irregular internal contours in an enlarged ovary12 (Level III). They are often highly vascular and mimic ovarian neoplasms12 (Level III). The appearance of virilizing symptoms in the pregnant patient leads to this diagnosis. When a luteoma is suspected, laparotomy can be avoided during pregnancy because the lesions regress after delivery12 (Level III).

Paraovarian lesions are virtually always from a benign etiology and therefore do not require surgical intervention during pregnancy. Paraovarian cysts are common benign lesions usually 1 to 2 cm in size appearing as simple, anechoic structures. The sonographic appearance of a hydrosalpinx is characteristically an elongated tubular cystic structure with incomplete septations or nodules from thickened endosalpingeal folds5 (Level III).

Leiomyomas are the most common solid adnexal masses found during pregnancy. Sonographic appearance is variable depending on whether the myoma has undergone degeneration, infarction, or necrosis. Tubo-ovarian abscess is another adnexal mass where the normal morphological pattern of the ovary is lost and replaced by a complex cystic structure. There are also nongynecologic causes of adnexal masses that need to be considered during pregnancy including acute appendicitis, irritable bowel disease, or adhesive disease from prior surgeries.

When an ovarian cyst is complex (and not hemorrhagic), the likelihood of neoplasm is increased. The most common malignancies during pregnancy are germ cell tumors, stromal or epithelial tumors of low malignant potential (LMP).15 Dysgerminoma is a type of germ cell tumor accounting for less than 5% of ovarian cancers overall. It is the most common invasive malignant neoplasm in pregnancy (excluding epithelial tumors). Sonographic appearance of dysgerminomas is likely to be a solid mass with anechoic areas from hemorrhage or necrosis. Prognosis is very good as it is sensitive to chemotherapy and radiation. Sex-cord stromal tumors such as fibromas, thecomas, or granulose cell tumors, although uncommon overall, are potential malignancies detected during pregnancy.

Epithelial neoplasms include cystadenomas, cystadenocarcinomas, and tumors of low malignant potential (LMP). Cystadenomas may be simple cysts or have thin septations. Serous cystadenomas are the most common type with 20% being bilateral. They tend to be anechoic, whereas mucinous tumors have low-level internal echoes with multiple septations. Approximately 10% to 15% of cystadenomas are of LMP which have cytological features of malignancy without evidence of stromal invasion5 (Level III). Irregular septations, mural nodules, and increased vascularity by color Doppler interrogation on ultrasound increase the likelihood of malignancy.

The management of asymptomatic adnexal masses that persist during pregnancy remains controversial. Traditionally, these patients are treated by exploratory laparotomy and tumor resection at 16 to 20 weeks of gestation despite the lack of supporting data12 (Level III). Surgery is performed to rule out malignancy and prevent complications such as torsion, cyst rupture, and obstruction of labor. Abdominal surgery during pregnancy is associated with its own complications, including spontaneous miscarriage, rupture of membranes, preterm labor, and preterm birth12 (Level III). Advances in ultrasonography have caused practitioners to question whether surgical intervention is warranted in all pregnant patients with adnexal masses.

Observation has therefore been proposed for select patients with an adnexal mass during pregnancy8,13 (Level II-2, Level III). To our knowledge, no prospective studies randomizing between observation and surgery have been performed. Schmeler et al (2005) performed a retrospective study whereby they reviewed the records of women with adnexal masses greater than 5 cm during pregnancy (N = 59) and evaluated the circumstances of each case as well as final outcome. Seventeen (29%) of these women had surgery and 42 (71%) were observed during pregnancy then underwent cystectomy or oophorectomy at time of cesarean section. Two of the surgical cases were by laparoscopy and the rest via laparotomy. Five of 17 (29%) surgical cases were diagnosed with a malignancy on final pathologic analysis. None of those cases which were observed had a malignancy. All of the malignant masses had complex features on ultrasonography compared with 30% of benign cases13 (Level III). The authors propose that in select cases, close observation is a reasonable alternative to antepartum surgery in patients with an adnexal mass during pregnancy.

Tumor Markers in Pregnancy
In general, CA-125 levels are not useful because CA-125 can be elevated in pregnancy, especially in the first trimester and again at time of delivery. During the second and third trimesters, serum levels were below 35 U/mL16 (Level II-2). Although alpha-fetoprotein (AFP) screening is used to detect neural tube defects, markedly elevated AFP levels are seen with endodermal sinus tumors17 (Level III). As for lactate dehydrogenase (LDH), it does not change in pregnancy and therefore can be assayed in pregnancy to follow the course of a dysgerminoma.

Comprehension Questions

42.1 A 31-year-old G1P0 woman presents to your office at 32 weeks of gestation with an adnexal mass which is described on sonogram as having a complex echo pattern and calcified material. There is no free fluid and the mass is 5 cm. What is the most likely diagnosis?
A. Benign cystic teratoma
B. Hemorrhagic corpus luteum cyst
C. Ovarian hyperstimulation syndrome
D. Theca lutein cyst

42.2 A 29-year-old G1P0 woman at 10 weeks of gestation presents with an adnexal mass of 4 cm in size that is thin walled without septations or projections. What is the best management for this patient?
A. Perform immediate exploratory laparotomy and staging procedure.
B. Perform a laparoscopic excision of mass during second trimester.
C. Repeat ultrasound in the second trimester.
D. Refer her to a gynecologic oncologist for the remainder of her pregnancy.

42.3 A 19-year-old G2P1001 woman at 15 weeks’ gestation is noted to have a 9 cm adnexal mass. She complains of abdominal pain that is crampy in nature and associated with nausea and vomiting. Which of the following is the most likely diagnosis?
A. Abruptio placenta
B. Chorioamnionitis
C. Ovarian torsion
D. Rupture of membranes


42.1 A. Teratomas are the most common benign ovarian neoplasm diagnosed in pregnancy and the mass described in this example is consistent with the sonographic features of a teratoma.

42.2 C. This adnexal mass is small (< 8 cm) and simple, and is most likely a physiologic cyst. Simple cysts that are less than 5 cm usually resolve by the second trimester and therefore observation is the best approach.

42.3 C. Ovarian torsion is a potential complication of an adnexal mass during pregnancy. This is a clinical diagnosis. Doppler flow studies of the ovarian vessels may or may not be helpful.

Clinical Pearls

See US Preventive Services Task Force Study Quality levels of evidence in Case 1
➤ Almost 100% of simple cysts smaller than 5 cm will resolve spontaneously by second trimester (Level III).
➤ Malignancy is most likely with thick-walled cyst,containing thick septations and internal projections. Increased flow by color Doppler in this setting is also suspicious (Level II-3).
➤ Adnexal masses greater than 5 cm are at risk for torsion, rupture, and sometimes labor obstruction in pregnancy (Level II-3).
➤ Risks of abdominal surgery during pregnancy include spontaneous miscarriage,rupture of membranes,preterm labor,and preterm birth (Level III).
➤ If surgical intervention can be planned and is necessary,performing it during the early second trimester is recommended (Level III).


1. Leiserowitz GS. Managing ovarian masses in pregnancy. Obstet Gynecol Surv. 2006;61(7):463-470. A thorough review article on the management of adnexal masses during pregnancy including the use of diagnostic testing and options for treatment (Level III). 

2. Bernard LM, et al. Predictors of persistence of adnexal masses in pregnancy. Obstet Gynecol. 1999;93:585-589 (Level II-2). 

3. Zanetta G, Mariani E, Lissoni A, et al. A prospective study of the role of ultrasound in the management of adnexal masses in pregnancy. BJOG. 2003;110:578-583. A large prospective cohort study of pregnant women with adnexal masses of greater than 3 cm who underwent observation or surgery based on sonographic appearance. The authors conclude that expectant management is successful in majority of cases with low incidence of malignancy or antepartum complications (Level II-2). 

4. Whitecar MP, Turner S, Higby MK. Adnexal masses in pregnancy: a review of 130 cases undergoing surgical management. Am J Obstet Gynecol. 1999;181:19-24. A review of 130 cases of adnexal masses in pregnancy which showed that emergent surgery does not increase the risk of adverse pregnancy outcome (Level III). 

5. Glanc P. Adnexal masses in the pregnant patient: a diagnostic and management challenge. Ultrasound Q. 2008;24(4):225-240 (Level III). 

6. Nelson MJ, Nelson MJ, Cavalieri R, Graham D, Sanders RC. Cysts in pregnancy discovered by sonography. J Clin Ultrasound. 1986;14:509-512 (Level II-3). 

7. Fleischer AC, Boehm FH, James AE Jr. Sonography and radiology of pelvic masses and other maternal disorders. Semin Roentgenol. 1982;17:172-181 (Level II-3). 

8. Thorton JG, and Phelps RL. Ovarian cysts in pregnancy: does ultrasound make traditional management inappropriate? Obstet Gynecol. 1987;69:717-720 (Level II-2). 

9. Ghossain MA, Buy JN, Ruiz A, et al. Hyperreactio luteinalis in a normal pregnancy: sonographic and MRI findings. J Magn Reson Imaging. 1998;8:1203-1206 (Level III). 

10. Baltarowich OH, Kurtz AB, Pasto ME, Rifkin MD, Needleman L, Goldberg BB. The spectrum of sonographic findings in hemorrhagic ovarian cysts. AJR Am J Roentgenol. 1987;148:901-905 (Level III). 

11. Ritchi WGM. Ultrasound evaluation of normal and induced ovulation. In: Callen PW (ed). Ultrasonography in Obstetrics and Gynecology. 3rd ed. Philadelphia, PA: WB Saunders Co; 1994:582 (Level II-3). 

12. Chiang G, and Levine D. Imaging of adnexal masses in pregnancy. J Ultrasound Med. 2004;23:805-819 (Level III). 

13. Schmeler KM, Mayo-Smith WW, Peipert JF, Weitzen S, Manuel MD, Gordinier ME. Adnexal masses in pregnancy: surgery compared with observation. Obstet Gynecol. 2005;105(5):1098-1103. Between 1990 and 2003, 127,177 deliveries were performed at our institution. An adnexal mass 5 cm in diameter or greater was diagnosed in 63 (0.05%) patients. Antepartum surgery was performed in 17 patients (29%): 13 because of ultrasound findings that suggested malignancy and 4 secondary to ovarian torsion. The remaining patients were observed, with surgery performed in the postpartum period or at the time of cesarean delivery. The majority of masses were dermoid cysts (42%). Four patients were diagnosed with ovarian cancer (6.8% of masses, 0.0032% of deliveries), and one patient (1.7%) had a tumor of low malignant potential. Antepartum surgery due to ultrasound findings that caused concern was performed on all five women diagnosed with a malignancy or borderline tumor, compared with 12 (22%) of the patients with benign tumors (P < 0.01). The authors conclude that in select cases, close observation is a reasonable alternative to antepartum surgery in patients with an adnexal mass during pregnancy (Level III). 

14. Choi JR, Levine D, Finberg H. Luteoma of pregnancy: sonographic finding in two cases. J Ultrasound Med. 2000;19(12):877-881. 

15. ACOG Practice Bulletin. Management of adnexal masses. Obstet Gynecol. 2007 Jul;110(1):201-214. 

16. Kobayashi F, Sagawa N, Nakamura K, et al. Mechanism and clinical significance of elevated CA-125 levels in sera of pregnant women. Am J Obstet Gynecol. 1989;160:563-566. CA-125 was found to peak at 10 weeks gestation and again at the time of delivery. During the second and third trimesters, serum levels were below 35 U/mL. CA-125 is very high in the amniotic fluid during the second trimester. These investigators conclude that elevated CA-125 levels in maternal sera are found at the time of chorionic invasion or placental separation (Level II-2). 

17. Christman JE, Teng NN, Lebovic GS, Sikic BI. Delivery of a normal infant following cisplatin, vinblastine, and bleomycin (PVB) chemotherapy for malignant teratoma of the ovary during pregnancy. Gynecol Oncol. 1990;37:292-295 (Level III).


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