Address correspondence to: Thangam R. Varma, PhD, FRCS, FRCOG Senior Lecturer & Consultant OB&GYN, St. George"s Hospital & Medical School, Cranmer Terrace, London SW17 ORE, UK Ph: 081-672-9944 Fax: 081-767-9585.

Synonyms: None.

Definition: An ovarian cyst is a fluid-filled ovarian tumor.

Prevalence: It is a rare condition, and little more than 100 neonatal cases have been reported.

Etiology: The majority are benign cysts of germinal or Graafian origin.

Pathology: These are benign, functional cysts which result from enlargement of otherwise normal follicles known to be present during the third trimester and early neonatal period.

Associated anomalies: Associated congenital pyloric stenosis, hydrocephalus, agenesis of the corpus callosum, and fetal hypothyroidism have been reported.

Differential diagnosis: Hydrometrocolpos, obstructive uropathy, anorectal atresia, persistent cloaca, and urachal cyst.

Prognosis: Excellent if an isolated, unilateral and unilocular ovarian cyst is seen, since most are benign.

Management: Standard obstetrical care.

MESH Ovary, cyst CDC 752.085 ICD9 752.0

Introduction

A wide variety of cystic masses can be observed in the fetal abdomen (Table 1). Excluding cystic masses arising from the urinary system (hydronephrosis, multicystic dysplastic kidneys, paranephric pseudocysts, hydroureter, distended bladder) or dilated bowel, the most common causes of intra-abdominal cystic mass include an ovarian cyst, meconium pseudocyst, enteric duplication cyst, or mesenteric cyst^1,2.

Awareness of the usual prevalence, location, and sonographic appearance of cystic lesion can help suggest the most likely diagnosis. A cyst in the pelvis of a female fetus is most likely to be an ovarian cyst, hydrometrocolpos, persistent cloaca or enlarged distended bladder.

Case report

The mother was G₃P₁ and she was booked to have her second child at St George"s Hospital when she was 15 weeks pregnant. She was 30 years old and had a normal pregnancy and delivery in 1991 and had a healthy baby girl weighing 3 kg. Prior to this pregnancy, she had a miscarriage at 6 weeks in 1990.

She had her first scan at 15 weeks gestation soon after her first visit to the booking antenatal clinic which confirmed her date, and no obvious problem was noted at the first ultrasonic examination. At 20 weeks gestation, she had a full anomaly scan which confirmed the date and normality of the fetus. At 32 weeks gestation, she had a repeat ultrasonic examination because the clinical examination suggested that the uterus was slightly bigger for the period of gestation. At this stage, the ultrasonic examination showed a well demarcated cystic lesion approximately 40 mm in diameter in the fetal abdomen (fig. 1-2).

Figure 1: Longitudinal view of the abdomen with cystic lesion above the bladder.

Figure 2: Transverse scan of the abdomen with cystic lesion.

There was no other abnormality detected either in the renal, genital or gastrointestinal tract of the fetus. The amniotic fluid was considered to be normal as well. Fetal growth and size revealed no abnormality except that the estimated fetal weight was shown to be above average. By exclusion process, it was thought that the lesion was probably an ovarian cyst, and the mother had two weekly scans to assess the size of the cystic lesion. The lesion remained the same as at 32 weeks gestation. No other abnormality was detected. The amniotic fluid column also was found to be normal (50-60 mm). The estimated fetal weight was 4000g at 40 weeks gestation.

Labor was induced 5 days after term because of a rise in maternal blood pressure. The mother progressed quickly and had a spontaneous vaginal delivery of a baby girl weighing 4160g with an Apgar score of 9 at 1 and 5 minutes. The pediatrician confirmed that the infant was a healthy female with a normal female genitalia and there was no evidence of any other abnormality. Ultrasonic examination of abdomen suggested she had a cystic lesion on the right side of the abdomen which measured 45mm in diameter.

The cystic lesion was lying anterior to the right kidney, and the kidneys, ureters, and bladder were found to be normal. There were few small cysts in the left ovary; each one measured 1-2 mm. The differential diagnosis was either a right-sided ovarian cyst or another embryological abnormality, such as mesenteric cyst. Since there was some possibility that spontaneous regression was possible, she was kept under observation and had four weekly ultrasonic examinations where the cyst was found to be persistent. Hence, it was decided by the pediatric surgeon to do a laparotomy and ovarian cystectomy. She was admitted for surgery and had an ovarian cystectomy on the right side. The left ovary had small cysts measuring 3-5 mm in diameter which were punctured. She made an excellent recovery. A histology report confirmed a benign ovarian cyst with no evidence of any other abnormality. She had a repeat ultrasonic examination at 6 weeks following surgery which showed no abnormality in the ovaries or in the rest of the abdomen or pelvis.

Discussion

Incidence

Ovarian cyst is a relatively a rare fetal condition. Approximately 100 neonatal cases have been reported in the literature.

Etiology

The majority are benign cysts of germinal or Graafian origin, such as simple cysts, thecca-lutein cysts, and corpus luteum cysts. These are benign, functional cysts which result from enlargement of an otherwise normal follicle known to be present during the third trimester and early neonatal period^3,4,5. Desa⁵ found small follicular cysts in 34% (113 of 332) of newborns and infants who died within 28 days of life. However, these cysts are usually too small, (usually less than 1 mm) to be visualized sonographically.

Evidence suggests that ovarian cysts result from excessive stimulation of the fetal ovary by placental and maternal hormones. It has been observed that there was slightly higher prevalence of ovarian cysts in the fetuses when the pregnancy was complicated by diabetes, pre-eclampsia, or rhesus immunization, presumably associated with excessive release of placental chorionic gonadotrophins by the enlarged placenta. Fetal hypothyroidism has also been associated with ovarian cysts, and the nonspecific stimulation of pituitary glycoprotein hormone synthesis has been thought to be a cause for the ovarian cyst^6,7.

Pathology

Unilateral cysts are more common than bilateral, and unilocular cysts, are more common than multilocular cysts. Size varies and ranges from small cysts to structures filling the entire abdomen. Granuloma cell tumors, benign cystic teratomas, and mesonephromas have been reported in newborns, but they are rare compared to the cysts of germinal origin^8,9.

Fetal ovarian cysts are the most common cause of intra-abdominal cysts reported antenatally, excluding renal and bowel etiologies.

Diagnosis

An ovarian cyst should be suspected when a female fetus has a cystic intra-abdominal mass which is separate from the organs of the urinary and gastrointestinal tract.

Sonographic findings

Ovarian cysts frequently have been diagnosed on prenatal sonography^10-16. In no case has a fetal ovarian cyst been reported before the third trimester.

The sonographic appearance of an ovarian cyst is variable, depending on its size or complications, such as hemorrhage or torsion. An uncomplicated ovarian cyst appears as a unilocular cystic lesion and is usually localized to the pelvis or lower abdomen. Most cysts are unilateral, and polyhydramnios has been reported in at least 10% of cases. When the cyst undergoes torsion or hemorrhages inside, the appearance may be complex or even solid^15,16.

Differential diagnosis

Table 2 shows the differential diagnoses for a cystic mass. The differential diagnoses include urachal and mesenteric cysts or enteric duplication cyst, duodenal atresia, and dilated bowel¹⁵. Identification of male gender would exclude ovarian cyst or hydrometrocolpos and make persistent cloaca or megacystic-microcolon intestinal hypoperistalsis (MMIHS) highly unlikely. Urachal cysts are single and anterior, extending from the bladder to the umbilicus. The shape of enteric bowel duplication is generally tubular; duodenal atresia has a typical double- bubble appearance, and polyhydramnios is the rule.

Associated anomalies

Fetal hypothyroidism⁷, agenesis of the corpus callosum¹⁷, and congenital hypertrophic pyloric stenosis have been reported associated with the diagnosis of antenatal ovarian cyst.

Prognosis

The majority of ovarian cysts undergo spontaneous regression and involution following delivery or even in utero. Birth dystocia and respiratory distress have been reported from very large cysts⁸. To avoid potential complications, such as torsion and hemorrhage, antenatal percutaneous aspiration of ovarian cysts has been suggested. In the newborn, large cysts may cause ascites, they may undergo torsion, infarction, and may lead to intestinal obstruction by membranous adhesions, rupture or bleed. Death may ensue because of massive hemoperitoneum. The frequency with which these accidents occur in utero is unknown.

Obstetrical management

The detection of fetal ovarian cyst does not usually alter standard obstetrical care. If the cyst is large and if soft tissue dystocia is suspected, an elective cesarean section is a logical approach. An alternative would be to drain the cyst under ultrasound guidance if it looks unilocular and simple. Serial ultrasound examinations during pregnancy are recommended to monitor the growth of the cyst and possible complications. Torsion and bleeding of a pedunculated ovarian cyst can be suspected by the layering echoes inside the cyst¹⁸ and by the change in the ultrasonic image of a hypoechogenic mass into a hyperechogenic one. Newborns with ovarian cysts should be evaluated for hypothyroidism and may also be assessed ultrasonically and may need surgery.

Conclusion

The case history presented in this paper highlights the importance of follow-up of the fetus during pregnancy to assess the size of the cystic lesion, and the subsequent management is no different than normal obstetrical management. The infant needs prompt follow-up scans and prompt management surgically if the cyst persists. The cysts are usually benign and may sometimes regress spontaneously after delivery, hence the importance of withholding surgery immediately after delivery.

References

1. Berdon WE, Baker DH, Wigges HJ, et al. Calcified intra-abdominal meconium in newborn males with imperforate anus. AJR 1975;125:449-455.

2. Lewis BD, Doubilet PM, Heller VL, et al. Cutaneous and visceral hemangiomata in the Klippel-Trenaunay-Weber syndrome: antenatal sonographic detection. AJR 1986;147: 598-600.

3. Carlson DH, Griscom NT. Ovarian cysts in the newborn. AJR 1972;116:664.

4. Bower R, Dehner LP, Ternberg JL. Bilateral ovarian cysts in the newborn. Am J Dis Child 1974;128:731-733.

5. Desa DJ. Follicular ovarian cysts in stillbirths and neonates. Arch Dis Child 1975;50:24-50.

6. Evers JL, Rolland R. Primary hypothyroidism and ovarian activity: evidence for an ovarlap in the synthesis of pituitary glycoproteins: case report. Br J Obstet Gynecol 1981;88:195.

7. Jafri SZH, Bree RL, Silver TM, et al. Fetal ovarian cysts: sonographic detection and association with hypothyroidism. Radiology 1984;150:809-812.

8. Carlson DH, Griscorn NT. Ovarian cysts in the newborn. AJR 1972;116:664.

9. Jouppila P, Kirkinen P, Tuononen S. Ultrasonic detection of bilateral ovarian cysts in the fetus. Eur J Obstet Gynecol Reprod Biol 1982;131:87.

10. Lee TG, Blake P. Prenatal fetal abdominal ultrasonography and diagnosis. Radiology 1977;124:475-477.

11. Crade M, Gillooly L, Taylor KJM. In utero demonstration of an ovarian cyst mass by ultrasound. JCU 1980;8:251.

12. O"Hagan DB, Pudifin J, Mickel RE, et al. Antenatal detection of a fetal ovarian cyst by real-time ultrasound. S Afr Med J 1985;67:471-475.

13. Ikeda K, Suita S, Nakano H. Management of ovarian cysts detected antenatally. J Pediatr Surg 1988;23:432-435.

14. McKeener PA, Andrews H. Fetal ovarian cysts: a report of five cases. J Pediatr Surg 1988;23:354-355.

15. Nussbaum AR, Sanders RC, Hartman DS, et al. Neonatal ovarian cysts: sonographic-pathologic correlation. Radiology 1988;168:817-821.

16. Rizzo N, Gabrielli S, Perolo A, et al. Prenatal diagnosis and management of fetal ovarian cysts. Prenat Diagn 1989;9:97-104.

17. Sandler MA, Smith SJ, Pope SG, et al. Prenatal diagnosis of septated ovarian cysts. JCU 1985;13:55.

18. Preziosi P, Fariello G, Maiorana A, et al. Antenatal sonographic diagnosis of complicated ovarian cysts. JCU 1986;14:196.

Originally published in The Fetus in 1994, posted 6/1999