Concurrent maternal and fetal ovarian cysts.

Due to improvements in ultrasonography, the detection of fetal abdominal masses has increased. We describe a case of co-existing maternal and fetal ovarian cysts in a 37-year-old primiparous woman. The fetal ovarian cyst was first identified in the third trimester and reached a maximum diameter of 9 cm. The maternal cysts were present from 20 weeks onwards; with a maximum diameter of 8 cm. Histological examination showed the maternal lesions were benign dermoid cysts. The fetal lesion resolved spontaneously by 5 months. This case illustrates that fetal and maternal ovarian cysts may co-exist and could potentially have a similar hormonal etiology.