A case series of chorioangiomas in placentas with clinical indication for histological examination.

Chorioangiomas are benign angiomas arising from chorionic tissue and they are the most common non-trophoblastic tumors of the placenta, as they are observed in 1% of all placentas examined. Most chorioangiomas are small and asymptomatic, often undetected during a prenatal ultrasound, and their clinical significance is still unknown. Large chorioangiomas, measuring more than 4-5 cm in diameter, can usually be detected prenatally by gray-scale or color Doppler sonography, and may be associated with maternal or fetal complications, such as preeclampsia, maternal mirror syndrome, preterm delivery, nonimmune fetal hydrops, fetal growth restriction and fetal demise. We herein describe the clinical-pathological features of a monocentric series of 30 placental chorioangiomas and discuss their clinical-pathological features and possible molecular mechanisms underlying their development.