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Images in Women's Health

Adnexal Mass in Pregnancy

Ashley S. Case, MD

CASE HISTORY

A 25-year-old woman, gravida 1, para 0, presented for routine prenatal ultrasonography at 15 weeks' gestation. Ultrasonographic findings included a 15-week, 6-day intrauterine pregnancy, as well as massive ascites in both the abdomen and pelvis extending from sidewall to sidewall and superiorly to the diaphragm. The ovaries could not be visualized. The patient had no medical problems other than obesity (298 lb).

Physical examination revealed no significant findings other than an obese abdomen with a positive fluid wave. The patient denied nausea, vomiting, early satiety, bloating, or any change in bowel habits. The patient's family felt that she had gained an excessive amount of weight during this pregnancy. The patient herself admitted to some abdominal swelling, but felt that it was simply related to her pregnancy.

DIAGNOSIS

A computed tomography scan of the abdomen and pelvis was performed, revealing a large, cystic lesion extending from the pelvis and occupying most of the abdominal cavity. It measured 36.5 x 15.4 cm (Figures 1 and 2). The mass demonstrated fluid density without wall thickening, septation, or enhancement. The liver, spleen, and all other organs appeared normal. There was no adenopathy or free fluid, and both ovaries appeared normal.

The patient subsequently underwent exploratory laparotomy with left ovarian cystectomy. More than 12 L of fluid were withdrawn from the cyst. Pathologic analysis revealed a benign mucinous cystadenoma. The patient recovered remarkably well and was discharged home on postoperative day 3. She has had no complications to date on follow-up, with a normal 24-week pregnancy.

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Figure 1 and 2. Figures 1 and 2. Computed tomography images of adnexal mass. Courtesy of Ashley S. Case, MD.

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DISCUSSION

Adnexal masses during pregnancy are relatively rare, with a reported incidence of 1/81 to 1/8,000 pregnancies.¹ Most of these adnexal masses are simple cysts, and 90% disappear as the pregnancy progresses.² The incidence of ovarian cancer in pregnancy is 1/8,000 to 1/20,000 deliveries.² Adnexal masses in pregnancy may present a clinical dilemma. Treatment decisions are often difficult because surgery involves risks and complications to the mother and the fetus, while conservative management may result in torsion, hemorrhage, rupture, dystocia, or spread of malignancy.

Ultrasonography is often useful in detecting pelvic masses and distinguishing cystic and solid features. Certain ultrasonographic features are worrisome (eg, papillary excrescences, septations). Other ominous features (eg, large size) may be nonspecific. The ultrasonographic detection rate for adnexal masses during pregnancy is approximately 1%.³ In their series of 130 cases, Whitecar et al¹ found that ultrasonography was not useful in identifying ovarian tumors of low malignant potential, and recommended laparotomy for all persistent masses. However, Bromley and Benacerraf³ studied 131 masses, and found that ultrasonography accurately characterized adnexal masses and correctly identified all malignancies. These differences may be due to the mass itself, the imaging quality, or the experience of the sonographer.

However, when considering the differential diagnosis, the physician must remember that ultrasonography is not a diagnostic test for adnexal malignancies. Computed tomography or magnetic resonance imaging may help to better distinguish the source, details, and spread of the mass. All suspicious masses require further evaluation or surgery to confirm the diagnosis.

Surgery is typically indicated for adnexal masses larger than 6 cm or for complex masses with suspicious features, regardless of whether pregnancy is present. Some studies suggest that the risk of malignancy alone justifies surgical intervention for persistent adnexal masses.¹ Whitecar et al¹ found 6.1% of patients in their series to have an adnexal mass that was either malignant or of low malignant potential. Studies recommend excision of an adnexal mass at 16 to 18 weeks' gestation to avoid the risk of spontaneous abortion that may occur when surgery is performed in the first trimester, and also to allow time for a benign cyst to resolve.¹ Patients undergoing laparotomy prior to 23 weeks' gestation have significantly fewer adverse outcomes than those who have surgery after 23 weeks.²

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CONCLUSION

This case demonstrates the appropriate procedure for evaluating and treating a large adnexal mass during pregnancy. The lesion was diagnosed as a mucinous cystadenoma, with a favorable outcome for both the patient and fetus.

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Ashley S. Case, MD, is resident, Department of Obstetrics and Gynecology, University of Alabama at Birmingham.

References

1. Whitecar MP, Turner S, Higby MK. Adnexal masses in pregnancy: a review of 130 cases undergoing surgical management. Am J Obstet Gynecol. 1999; 181(1):19-24.
2. Duic Z, Kukura V, Ciglar S, Podobnik M, Podgajski M. Adnexal masses in pregnancy: a review of eight cases undergoing surgical management. Eur J Gynaecol Oncol. 2002;23(2):133-134.
3. Bromley B, Benacerraf B. Adnexal masses during pregnancy: accuracy of sonographic diagnosis and outcome. J Ultrasound Med. 1997;16(7):447-452.

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