Rupture is a rare complication of ovarian cysts diagnosed during the prenatal period. We present a case that focuses on the postnatal sonographic appearance of rupture of an ovarian cyst after vaginal delivery. Histopathologic correlation is provided. The main sonographic features include complicated ascites and a collapsed cystic structure in the abdomen. Ruptured ovarian cyst should be included in the differential diagnosis of unexplained ascites in a newborn girl. A 3-kg female infant was born via spontaneous vaginal delivery at 34 weeks' gestation with APGAR scores of 9-9-9. Prenatal sonographic examination performed at 29 weeks' gestation had revealed a large distended anechoic cyst in the fetal abdomen measuring 11 Â 10 Â 8 cm ( Figure 1). The organ of origin was not known. On postnatal physical examination, the infant was noted to have a distended abdomen. A subsequent abdominal sonogram obtained on day 1 of life revealed a large amount of diffuse ascites containing septa and debris (Figure 2). The expected large distended abdominal cyst was not identified; instead, a smaller (%4 cm) complex cystic mass with a thick, irregular wall was identified in the right lower quadrant. The contour of the wall was redundant, suggesting a collapsed cyst. Small follicles were visible at the periphery of the lesion.The patient subsequently underwent laparotomy with excision of a ruptured right abdominal cystic lesion. Pathologic examination of the lesion revealed a 4 Â 4 Â 0.5-cm cystic structure with a uniformly thickened, smooth wall measuring 0.2 cm in thickness (Figure 3). The microscopic findings demonstrated ovarian tissue containing a cystic structure lined by focally denuded layers of granulosa cells, consistent with a benign follicular cyst of the ovary.
DISCUSSIONFetal ovarian cysts may be diagnosed during a second-or third-trimester sonographic examination and are typically unilateral. Risk factors for fetal ovarian cyst include elevated circulating levels of human chorionic gonadotropin, fetal follicle-stimulating hormone, and maternal estrogens. Maternal diabetes, fetal hyperthyroidism, and placentomegaly have also been implicated in the occurence of fetal ovarian cysts. 1,2 Histologically, ovarian cysts can be follicular (graafian) or lutein in nature. Typical sonographic features include a well-circumscribed anechoic or hypoechoic structure in the lower abdomen. Internal echoes, when present, reflect hemorrhage or organized hematoma. The presence of a fluid-debris level may indicate ovarian torsion. 3 The differential diagnosis for intra-abdominal fetal cystic structures includes ovarian, genitourinary, and gastrointestinal etiologies. Ovarian etiologies include follicular cyst, teratoma, and
