Abstract: Objective The common placental chorioangioma can be diagnosed by ultrasound examination. Alternatively, the aim of this study was to find the unusual sonographic characteristics for placental chorioangioma in order to raise the accuracy of prenatal diagnosis. Methods Clinical data of 20 patients with placental chorioangioma during pregnancy diagnosed in the hospital from January 2010 to June 2011 were analysed. According to prenatal ultrasonography [B-mode, 3D or color Doppler flow imaging,(CDFI)], clinical pathological characteristics and distinguishing from other placental tumors, unusual sonographic characteristics of placental chorioangioma were explored. Results Among 20 patients with placental chorioangioma during pregnancy, 10 patients(50%) were found to have definite the common ultrasound features;6 patients(30%) were discovered to have uncommon ultrasound features-smaller size of mass, CDFI: a strong signal showing blood flow into it;in 4 patients placental chorioangioma was misdiagnosed. Conclusion The common chorioangioma can be easily diagnosed by ultrasound examination, but sometimes some of placental chorioangioma was missed. Unusual sonographic characteristics of placental chorioangioma may help diagnose the unusual placental chorioangioma and raise the accuracy of diagnosis.

Key words: placental chorioangioma, sonographic characteristic, comparative analysis