P71Isolated choroid plexus cysts: a controversial morphologic sonographic marker for chromosomal abnormalities. Our experience in seven years (1993–1999)

Abstract

First reported by Chudleigh and colleagues in 1984 and considered ‘benign transient findings with no harmful sequelae’, an association between choroid plexus cysts and trisomy 18 was described by several following publications. Later on further studies have also suggested a significant risk for other chromosomal abnormalities, trisomy 21 in particular, so that literature data report an association between choroid plexus cysts and chromosomal abnormalities in about 8% of cases, more specifically in 1% if isolated and in 46% if associated with other malformations. As a consequence there are now different opinions on clinical significance and management, with some authors advocating karyotyping and others not. The aim of this study was to define the incidence of choroid plexus cysts in an unselected population and describe their association with aneuploidy. In the years 1993–99 a total of 10743 women from an unselected population attending a routine second‐trimester scanning were studied. Everyone underwent a detailed assessment of fetal anatomy by transabdominal sonography. In this period there were 27 fetuses in which choroid plexus cysts were the only sonographic abnormality, giving an incidence of 0.25% (in literature between 0.2 and 3.6%). Karyotyping was performed in only 12 cases, 11 normal and one trisomy 18. At birth the other 15 fetuses were normal. The incidence of aneuploidy was 3.70% (in according with literature review). We did not found association with other chromosomal abnormalities, trisomy 21 in particular. In the majority of cases the final risk remains small, but the presence of choroid plexus cysts increases the risk for aneuploidy, mainly trisomy 18. A need for further and wide studies about soft morphologic sonographic markers it’s necessary to better define their association with chromosomal abnormalities and as a consequence to better select the patients who need karyotyping, not underestimating that they appear in a large percentage of normal fetuses.To combine all the well‐known parameters (maternal and gestational age, serum biochemical screening, soft markers and nuchal translucency) seems to be the better way to adjust the risk of trisomy 21 and that of other chromosomal abnormalities, taking their different natural history into consideration.