EP16.38: A case of fetal XYY and Trisomy 5 mosaicism accompanied with thick and cystic placenta

Placentomegaly is the thickness of the placenta exceeding 4 cm in the umbilical cord insertion area. A thick placenta is associated with adverse perinatal outcomes including perinatal death, congenital anomalies, fetal growth restriction and pregnancy-induced hypertension. Cystic and thick placenta may also be associated with pathologies such as placental mesenchymal dysplasia and partial hydatidiform mole. A G1PO pregnant woman was referred to our clinic at 19+2/7 weeks of gestation due to the suspicion of the placental pathology. Ultrasonographic (USG) examination revealed thick and cystically degenerate placenta with fetal grade 1 hyperechoic bowel and polyhydramnios. Both chorionic villus biopsy and amniocentesis were performed due to the suspicion of partial hydatidiform mole, primary placental pathology and fetal genetic anomaly. As a result, no pathology was detected in the placental karyotype and pathological examination. As a result of amniocentesis culture, 48,XYY,+5[86]/47,XY,+5[1]/46,XY[13] chromosomal structure was detected. Upon the request of the family the pregnancy was terminated at 22+5/7 gestational weeks due to trisomy 5 mosaicism. In the pathological examination of the placenta, central cistern formation and hydropic congested edematous villi were observed in some regions. In conclusion, cystic and thick placenta is associated with adverse pregnancy outcome. In such cases, in addition to genetic and pathologic examination of the chorionic villi, fetal genetic examination by amniocentesis may also be recommended simultaneous. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.