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Key Points
The cause of fetal ovarian cysts is unclear but is most likely due to stimulation of the fetal ovaries by fetal gonadotropins, maternal estrogens, and placental chorionic gonadotropin.
Fetal ovarian cysts are most often unilateral but there have been reported cases that are bilateral.
Two types of cysts have been described: simple cysts and complicated cysts.
The antenatal natural history is variable with some cysts resolving, some becoming complex, most likely due to torsion, and some remaining stable.
Fetal intervention (cyst aspiration) is controversial but should be considered when the cyst is simple in nature and greater than 4 cm in diameter.
Delivery should occur in a center with appropriate pediatric surgical expertise available.
After delivery, the neonate should have an ultrasound to confirm the diagnosis.
Many simple cysts will resolve in the neonatal period. Surgery should be considered for complex cysts.
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Ovarian cysts arise from ovarian follicles. The primary stimulus for follicular development is follicle-stimulating hormone (FSH) secreted by the fetal pituitary, but maternal estrogens and placental human chorionic gonadotropin (hCG) also contribute to follicle growth in utero (Pryse-Davies and Dewhurst, 1971). Primary follicles can be seen as early as the 20th week of gestation, and graafian follicles first appear after 28 weeks of gestation (Pryse-Davies and Dewhurst, 1971; Peters et al., 1978). At birth, maternal estrogen and hCG levels decrease sharply, and FSH production is decreased by the inhibitory mechanism of the hypothalamus–pituitary–ovarian axis (Grumbach and Kaplan, 1975). This decrease in circulating estrogen and hCG levels at birth usually precludes the formation of simple ovarian cysts during childhood.
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Ovarian cysts develop from mature follicles in hormonally active ovaries and are therefore most often seen after puberty. The cause of fetal ovarian cysts is unclear but is most likely stimulation of the fetal ovaries by fetal gonadotropins, maternal estrogens, and placental chorionic gonadotropin. The increased incidence of ovarian cysts seen in infants of mothers with diabetes mellitus, rhesus sensitization, and preeclampsia—(conditions that are associated with excessive levels of serum chorionic gonadotropins (DeSa, 1975; Nussbaum et al., 1988)–-supports this pathogenesis. The association with fetal hypothyroidism has also been reported (Jafri et al., 1984). However, in most cases the cysts are detected in otherwise normal pregnancies (Sakala et al., 1991). It is most common for fetal ovarian cysts to be unilateral; however, bilateral fetal ovarian cysts have been reported. In the review by Sakala et al., (1991) of 65 cases of fetal ovarian cysts, 62 (95%) were unilateral, whereas 3 were bilateral.
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Ovarian and genital abnormalities account for 20% of all newborn abdominal masses, second only to those of urinary-tract origin (Griscom, 1965; Wilson, 1982). The first report of prenatal diagnosis of a fetal ovarian cyst was by Valenti et al. ...