Ovarian cyst in female fetus at 34 weeks' gestational age

Coronal sonogram shows complex cystic mass (arrow) in left abdomen (s = stomach, b = bladder). Through-transmission is seen posterior to cyst. On follow-up scans (not shown), cyst size remained the same but hematoma in cyst decreased in size. Excision was performed when infant was three months old, and pathology revealed intrauterine ovarian torsion.