Intrauterine ovarian dermoid cyst complicated by torsion: an uncommon presentation of abdominal mass in a neonate.

Fetal ovarian cysts are the most common abdominal masses in the female fetuses and believed to be caused by exposure of fetus to maternal and placental hormones. Majority of them are diagnosed in third trimester and should be distinguished from other causes of abdominal masses of genitourinary and gastrointestinal origin. Once diagnosed serial ultrasound monitoring is recommended to document changes in size or appearance. Complications like torsion or rupture merit careful assessment and surgical intervention to preserve ovarian function and fertility. We report a case of intrauterine ovarian dermoid cyst complicated by torsion, which was diagnosed prenatally on ultrasound as complex cystic lesion within the abdomen.