Karyotyping of fetuses with isolated choroid plexus cysts is not justified in an unselected population.

Abstract

The main objective of this study was to determine whether isolated choroid plexus cysts are a risk factor for trisomy 18. A total of 12,672 unselected patients were examined, and the outcome of fetuses with choroid plexus cysts was assessed. The cases with choroid plexus cysts were selected from the 12,672 patients and further divided into cases with minor markers of aneuploidy and cases with associated structural anomalies. Previous similar work was reviewed, analyzed, and, where possible, compared with the results of this study. The findings revealed 366 fetuses with choroid plexus cysts (2.9%). Thirty-three percent of fetuses with trisomy 18 had choroid plexus cysts, and, in every case, structural anomalies were also present. From the 12 cases with choroid plexus cysts in addition to major associated anomalies, amniocentesis revealed 2 cases of trisomy 18. Forty-three patients who had choroid plexus cysts and minor anomalies within our population had normal outcomes. These results indicate that the risk of amniocentesis is not acceptable if isolated choroid plexus cysts are isolated findings. More data are needed to establish whether choroid plexus cysts and other soft signs independently increase the risk of aneuploidy.