Evolution of first-trimester subchorionic hematoma into a large symptomatic placental cyst: A case report

Abstract

Background: Placental cysts are rare, often incidental findings. Large cysts (>4.5 cm) are clinically ominous due to their association with fetal growth restriction (FGR).Case Presentation: A 28-year-old primigravida presented at 6 weeks with a 2.9 cm subchorionic collection. By 35 weeks, this evolved into a 3.9 cm placental cyst at the cranial end, complicated by oligohydramnios (AFI 4-5 cm) and late-onset FGR. Following induction at 38 weeks, a 2.856 kg healthy boy was delivered. Gross examination revealed a blood-filled cyst delivered just before the placenta.Conclusion: Persistent first-trimester hematomas may serve as precursors to significant placental cysts. Serial monitoring via ultrasound and Doppler is vital to manage associated risks of FGR and oligohydramnios.