Second-trimester sonography and trisomy 18: the significance of isolated choroid plexus cysts after an examination that includes the fetal hands.
OBJECTIVE
To estimate the risk of trisomy 18 with the finding of isolated choroid plexus cysts after a standard sonographic examination that is extended to include the fetal hands.


METHODS
Aretrospective chart review was performed on all fetuses with choroid plexus cysts on second-trimester sonographic examinations. When choroid plexus cysts were identified, our standard protocol for fetal evaluation was expanded to include the hands. If no other findings were noted on completion of this examination, the choroid plexus cysts were classified as "isolated." These results were correlated with the presence or absence of trisomy 18 to determine the impact of this approach for the detection of fetuses with this aneuploidy.


RESULTS
From March 1990 to the end of 2001, 49,435 fetuses that were subsequently delivered at our hospital were scanned between 16 and 25 menstrual weeks. At least 1 choroid plexus cyst was detected in 1209 fetuses (2.3%), of which 1060 were isolated. No fetuses with isolated choroid plexus cysts had trisomy 18. However, 3 fetuses with trisomy 18 had choroid plexus cysts and abnormal hands as their only abnormal findings.


CONCLUSIONS
Fetuses with an apparently isolated finding of choroid plexus cysts can be further evaluated by extending the standard examination to include the hands. If no other findings are identified, the risk of trisomy 18 appears to be low.
Division of Fetal Imaging, Department of Obstetrics and Gynecology, William Beaumont Hospital, Royal Oak, Michigan 48073, USA. rabronsteen@beaumont.edu
Richard
R
Bronsteen
Wesley
W
Lee
Ivana M
IM
Vettraino
Raywin
R
Huang
Christine H
CH
Comstock
D000328:Adult; D002831:Choroid Plexus / Q000000981:diagnostic imaging*; D002887:Chromosomes, Human, Pair 18; D003560:Cysts / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D014314:Trisomy / Q000175:diagnosis*; D016216:Ultrasonography, Prenatal