Trisomy 16 causing pure trophoblastic mosaic

case report

Abstract

The trisomy of chromosome 16 is a rare disease. In most pregnancies with this disease, the accessory chromosome can be found in both the placenta and the fetus. Trisomy confined to the placenta is even rarer and is often identified in the placental region with a structurally normal fetus. Abnormalities that can be visualized at prenatal ultrasound in trisomy confined to the placenta are nonspecific and only contribute to have a suspicion about the presence of a chromosomal abnormality. A fetus with intrauterine growth restriction, congenital heart defects and congenital diaphragmatic hernias can be visualized. Ultrasonography serves not only to investigate fetal changes, but also to aid in chorionic villus sampling and amniocentesis to collect fetal samples for cytogenetic analysis. In suspected chromosomal abnormalities, serial ultrasound examinations are necessary to follow up the pregnancy. The present article aimed to report a case of trisomy confined to the placenta and the postnatal outcome.