Placental Chorioangioma: A Rare and Often Overlooked Cause of Polyhydramnios

Copyrightⓒ2026 by The Korean Society of Maternal and Child Healthreported in pregnant women with Fontan circulation and in those residing at high altitudes is suggestive of hypoxiadriven angiogenesis mediated by overexpression of angiogenic cytokines (Fan & Skupski, 2014).Maternal hypertension, diabetes, and female fetuses have been more frequently associated with chorioangiomas; however, data on genetic factors remain limited (Guschmann et al., 2003).Most chorioangiomas are small, asymptomatic, and often undetectable on routine prenatal ultrasonography.However, these occasionally grow into large masses, exceeding 15 cm in diameter (Kesrouani et al., 2013).Tumors measuring greater than 4-5 cm in diameter are classified as large chorioangiomas and are more likely to be detected.Nevertheless, these occur in approximately 1 in 10,000 pregnancies and can be overlooked or diagnostically challenging (Guschmann et al., 2003). PERINATAL COMPLICATIONS AND PROGNOSTIC FACTORSLarger (>4 cm) or multiple tumor lesions are associated with increased risks of adverse perinatal outcomes, primarily due to hemodynamic disturbances from abnormal arteriovenous shunting within the tumor (Buca et al., 2020;Wu et al., 2025).As the tumor enlarges, it may function as an arte riovenous shunt leading to high-output cardiac failure in the fetus.This can result in nonimmune hydrops fetalis, cardio megaly, polyhydramnios, increased midcerebral artery velocity, and congestive heart failure (Fan & Skupski, 2014).Consistent with these pathophysiologic mechanisms, a large 10-year study including 175 cases of placental chorioangioma reported that approximately one-third of pregnancies complicated by large tumors (≥4 cm) were associated with severe ORCID