Is Genetic Amniocentesis Warranted When Isolated Choroid Plexus Cysts Are Found?

Abstract

Our aim was to evaluate the prevalence of trisomy 18 in the setting of isolated fetal choroid plexus cysts and then to consider the risk of trisomy 18 versus the risks of genetic amniocentesis. Fetuses with choroid plexus cysts were prospectively obtained from a total mid‐trimester population of 18 861 fetuses with known outcomes. If the fetuses had trisomy 18, they were part of the study group and part of the control group if they had normal karyotypes. Scans were retrospectively reviewed for the characterization of cysts according to size, laterality, and appearance (simple or complex echo patterns). Chi‐square analysis of contingency tables of results was performed. 208/18 861 (1·1 per cent) fetuses had choroid plexus cysts. 201/208 (96·6 per cent) were normal fetuses or newborns, while 7/208 (3·4 per cent) of the fetuses with choroid plexus cysts had trisomy 18. Overall, 16 fetuses had trisomy 18 and seven (44 per cent) of these had choroid plexus cysts. 0/16 fetuses had choroid plexus cysts as the only sonographic finding. Although laterality or complexity of the cysts did not correlate with the presence or absence of a cytogenetic abnormality, cysts ⩾10 mm were more often associated with trisomy 18 than with a normal karyotype (P<0·01). We conclude that the discovery of choroid plexus cysts in otherwise normal fetuses in the late second trimester does not by itself justify the risks of genetic amniocentesis.

Sonographic markers of fetal trisomies: second trimester.

“…6). [28][29][30][31][32] Such large cysts undoubtedly take longer to resolve, supporting observations that delayed resolution of choroid plexus cysts carries an increased risk for trisomy 18. Whether the cysts are unilateral or bilateral does not appear to be significant, although it is probably true that large cysts also tend to be bilateral.…”

Acute triventricular hydrocephalus caused by choroid plexus cysts: a diagnostic and neurosurgical challenge

“…The current recommendation for antenatal detection of a choroid plexus cyst includes further testing for associated anomalies, and genetic counseling. 8 Although most of the cysts that are less than 1 cm in diameter remain asymptomatic, those that are larger than 2 cm are more often associated with headaches and obstructive hydrocephalus. 10 These symptoms may be acute (such as in every case of our series) and dramatic.…”

Choroid Plexus Cysts

“…In the second trimester, the incidence of CPC has been estimated by several population studies to be 1%, 3,4,[13][14][15][16][17][18][19] and other studies have found the incidence to vary from 0.18% to 3.6%. 20,21 Despite the low incidence, CPC has clinical implications for aneuploidy because of an association of choroid plexus with trisomy 18 2,[5][6][7][8][9][10][11][12]22 and trisomy 21.…”

“…4,10,13,19,[22][23][24] Researchers have been more concerned with trisomy 18 because the prevalence of CPC for fetuses with trisomy 21 and for the general population are the same. 13,23,24 Prenatal sonography in 44% to 50% of pregnancies with trisomy 18 show CPC, 15,16 whereas only 1.4% of pregnancies with trisomy 21 show CPC. 13 Approximately three fourths of abnormal fetal karyotypes associated with choroid plexus cysts are trisomy 18 and one fourth are trisomy 21.…”

“…10,30 -33 However, cysts with diameters less than 5 mm may not be linked with trisomy 18, 14,19 and large cysts in excess of 10 mm may impart a higher risk. 16,34 Furthermore, the risk for trisomy 18 when compared with normal births has been shown to increase with the presence of CPC without any other sonographic abnormalities, ie, isolated choroid plexus. Studies have estimated the likelihood ratio from 3.5 to 9 and risk from 1/30 to 1/477.…”