Fetal ovarian cysts: Prenatal diagnosis, management and postnatal outcome

With an incidence estimated at greater than 30%, ovarian cysts are the commonest abdominal tumor in newborn girls. Most cysts are small and involute within the first months. Their chief importance may be as part of the differential diagnosis of intra-abdominal masses. This study of 64 fetal ovarian cysts sought to learn whether sonographic findings relate to postnatal course of these structures, focusing on the need for surgical removal. The lesions in this study were diagnosed prenatally in the years 1986-1999. All cysts were detected in the third trimester at a median of 35 weeks' gestation. The cyst resolved spontaneously in 53% of cases, prenatally in 18 instances and postnatally in 16. Cysts that resolved prenatally were diagnosed at a median of 33 weeks' gestation and were no longer detected after 38 weeks. In most of these cases a preliminary decrease in size was documented. Cysts that resolved postnatally were in the same size range as those resolving before birth. Most operations were done because of cyst complications, which seemed to be more frequent in smooth-walled cysts. Twenty-nine follicular cysts and a single teratoma were removed in the first 2 weeks of liFe. Twelve infants, 11 with a hemorrhagically infarcted ovary and the 1 with a teratoma, had ovariectomy. Eight of these 12 infants had a cyst with internal structure on prenatal sonography. Three infants had prenatal aspiration of an ovarian cyst, but two of these cysts recurred and had to be fenestrated postnatally. A fetal ovarian cyst is, in general, not a life-threatening lesion. Some of these hormone-dependent cysts resolve spontaneously. The authors plan for spontaneous term delivery and carry out sonographic monitoring postnatally.