Fetal ovarian torsion appearing as a solid abdominal mass.

Fetal and neonatal ovarian cysts can be small asymptomatic lucencies or large symptomatic echocomplex masses that can cause intestinal obstruction and peritonitis. Solid masses are the most rare form of ovarian cysts. A fetus, anatomically unremarkable at 16 weeks' development, was found at 35 weeks to have a 5 x 5 cm solid mass. After delivery a laparotomy was performed, and a torsed ovary measuring 8 x 7 cm was removed. The infant did well after the procedure. Over 400 cases of perinatal ovarian cysts have been reported in the literature. Only 1% of these are purely echodense. When a fetal abdominal mass is present, separate from bowels and kidneys, a torsed ovary should be considered in the differential diagnosis. Management of the pregnancy and infant may be guided by the fetus or neonate's symptoms.