Background: Large subchorionic cysts usually arise close to the placental cord insertion site (PCIS) inducing traction on the umbilical cord, impairing blood flow and favoring fetal growth restriction (FGR). Intracystic hemorrhage/hematoma is likely due to the prothrombotic properties of X cells secretion (extravillous trophoblast), which line the cyst wall. Case report: We describe a large subchorionic cyst located exactly at the PCIS, displacing the umbilical cord vessel branches running along the cyst surface. The fetus presented with FGR. At 36 weeks of gestational age, the cyst measured 7.7 cm in maximum dimension showing a partially organized hemorrhage and a peripheral laminated thrombohematoma. The patient underwent elective cesarean section as the cyst and its vessels were at high risk of rupture during labor. Conclusion: Recognition of large subchorionic cysts close to or at the PCIS in a growth restricted fetus with subsequent expedited delivery may avoid a fatal event.
Keywords: Subchorionic cyst; fetal growth restriction; intracystic hemorrhage; placental cord insertion site; ultrasound and color Doppler ultrasound.