The apparently isolated choroid plexus cyst: importance of minor abnormalities in predicting the risk for aneuploidy.

OBJECTIVES

To assess the risk of aneuploidy in cases of isolated choroid plexus cysts (CPCs) and to compare the risk when associated with minor or major anomalies.

METHODS

All fetuses with CPCs and known karyotype were identified. CPCs were categorized as 'isolated' or associated with minor or major sonographic anomalies. Preexisting risk factors for aneuploidy were compared between groups. The frequency of aneuploidy was compared between fetuses with isolated CPCs and those with CPCs associated with minor or major anomalies. Continuous and categorical variables were analyzed using one-way analysis of variance or chi-square as appropriate with p < 0.05 considered significant.

RESULTS

One hundred and forty-nine fetuses with CPCs diagnosed at a mean gestational age of 19 weeks were identified. No significant differences in the frequency of preexisting risk factors for aneuploidy were identified between groups. Eighteen of 149 (12%) fetuses with CPCs had other sonographic anomalies; in 10 they were minor, and 2 of the 10 had abnormal karyotypes. Four of 8 fetuses with major anomalies were aneuploid. All 131 fetuses with isolated CPCs had normal karyotypes, and all aneuploid fetuses had additional anomalies.

CONCLUSIONS

The overall rate of aneuploidy in patients with CPCs was 4% with no abnormal karyotypes among isolated CPCs. The presence of even minor sonographic abnormalities substantially increased the risk of aneuploidy. Isolated CPCs identified sonographically may not place the patient at risk of aneuploidy, but should prompt a diligent search for other minor or major anomalies. The finding of any other anomaly warrants consideration for karyotypic evaluation.