Dr. Nupur Shah after pursuing postgraduation in OBGY, Dr. Nupur Shah completed her fellowship in Fetal Medicine at Apollo Centre of Fetal Medicine, New Delhi, followed by training under Prof. Kypros Nicolaides and Dr. Vita Zidere at King’s College Hospital, UK. She has worked as a Senior fellow in Apollo Hospitals, New Delhi. She is now working as a Consultant Fetal Medicine at Paras Bliss Fetal Medicine Centre, near Chandigarh with special interests in elastography, fetal interventions, fetal echocardiography and genetic syndromes
Introduction and Objective: Fetal choroid plexus cysts(CPC) are often detected on prenatal ultrasounds and posea need to formulate protocol for management andcounseling.
Methodology: A total of 1024 unselected cases between gestational ages 11 and 20 weeks were sonologically screened for CPC in 1-year period. On ultrasound, CPC are seen as sonolucent spaces in the echogenic choroid plexus of lateral ventricles of brain measuring at least 2–3 mm indiameter. Those diagnosed with CPC were subjected to thorough anomaly scan. Prenatal karyotype was offered in cases of associated anomalies.
Results: The incidence of CPC is 1% (10/1024) in this study. Associated anomalies were found in 20% (2/10) of cases, which were offered invasive testing for fetal kary-otype. All the cases with isolated CPC had good outcome.
Conclusions: Isolated CPC with low-risk biochemical screening for a neuploidies are now considered normal variants rather than a pathology, need no invasive testing and carry a good prognosis. CPC associated with other anomalies warrant invasive testing and are more likely to be associated with Trisomy 18.
Keywords : Choroid plexus cyst, Prenatal, Fetal, Trisomy 18
Fetal choroid plexus cysts detected during the prenatal ultrasounds incur a need to formulate a protocol on what else to be done, how to counsel the parents and when to offer invasive genetic testing. This study in an Indian scenario aims to answer these questions.
This study is a prospective study including a total of 1024 unselected cases between gestational ages 11 and 20 weeks during 1-year period (April 2016–March 2017). Theultrasound was carried out by FMF, UK (Fetal medicinefoundation) certified sonographer on WS80A, Samsung.The criteria for diagnosing choroid plexus cysts (CPC)were 1) sonolucent spaces within the echogenic choroidplexus of lateral ventricles, with well-defined walls 2)measuring at least 2–3 mm in mid trimester 3) usuallyfound at the level of atria, infrequently in the body oranterior part of choroid plexus [1]. Ten cases were reportedto have unilateral or bilateral choroid plexus cysts. Out often cases of CPC, only one was located in anterior part ofchoroid plexus. Rest all were located at the level of atria,the usual location.
All the cases wherein CPC were reported were thor-oughly scanned for other markers of Trisomy 18 likestrawberry head, clenched hands, cardiac abnormalities,talipes, early fetal growth restriction (FGR) and polyhy-dramnios. The biochemical screening risks (Dual marker orQuadruple marker as per gestation) for aneuploidies werealso reviewed in all ten cases. Two cases out of 10 hadassociated anomalies. One had clenched hands, early FGRand polyhydramnios and Trisomy 18 were suspected in thiscase, but parents denied any chromosomal analysis andintrauterine fetal death occurred at 28 weeks. Another casehad polyhydramnios and single umbilical artery as asso-ciated anomalies, and fetal karyotype was normal in thiscase. The case was followed up routinely until delivery of afemale 3.2 kg. The newborn was examined by the neona-tologist, and no peculiar features of genetic syndromeswere noted by him. Biochemical screening was low risk foraneuploidies in both the cases.
All the patients with isolated CPC were counseled aboutthe excellent prognosis and disappearance of cysts withadvancing gestation. All eight isolated cases were followedup at routine growth scans (32 or 36 weeks), and cysts hadalready disappeared in all of these (Figs.1,2)
The median age of the women included was 27.5 years. Allwomen belonged to South Asian ethnicity. None of thecases with CPC had a significant family history of genetic/chromosomal disorders. The incidence of CPC in our studyis 1%. The incidence of associated anomalies is 20% in ourstudy. Invasive testing was carried out in one of the twocases with associated anomalies as one couple denied theinvasive and carried the pregnancy expectantly. Postnatalexaminations of neonates having isolated CPC antenatallywere normal which reiterates good prognosis in isolatedcases. The association with chromosomal abnormalitiescould not be confirmed in our study which is ashortcoming.
Fetal choroid plexus cysts are most frequently transient andbenign findings, and therefore, there is a lack of patho-logical studies. The ultrasound appearance suggests that acollection of fluid surrounded by choroid plexus tissue [1].Choroid plexus cysts are identified in approximately 1–2%of fetuses in the second trimester, and they occur equally inmale and female fetuses [2]. The real incidence is probablydependent upon the resolution of the ultrasound equipmentand the alertness of the operator. The common differentialbeing intraventricular clot, but this is usually less regularthan CPC and associated with ventriculomegaly. Anotherdifficulty arises when cyst is located in anterior part of thebody or is unusually large. Transvaginal scan when fetus isin cephalic position or a follow-up scan to see the trend andruling out associated anomalies is helpful. Sometimes thereis no well-defined cyst, but the choroid plexus appearsheterogenous. This usually will be a benign finding inisolation [1].
Isolated CPC in prenatal period after thorough targetedanomaly scan are considered normal variants and not anabnormality. Ninety percent of CPC usually disappear bythird trimester (28 weeks) and rarely persist postnatally. Sofar, no evidence in the literature suggests proven neuro-logical damage or affected cognitive/motor behavior byCPC per se. A note is made in neurosurgical literature ofvery large cysts of the choroid plexuses causing intracra-nial hypertension postnatally, but these represent probablya separate clinical entity [1]. The likelihood of isolatedCPC being associated with Trisomy 18 is 7(2.5) and forTrisomy 21 is 1.9 [3,4]. No invasive genetic testing isneeded in these cases after thorough targeted anomaly scanand biochemical screen review. The overall counseling incase of isolated CPC should be of excellent prognosis, andthe parents be reassured. No difference in obstetric man-agement is required in these cases. Follow-up ultrasound isnot necessary for isolated CPCs [4].
In those with associated anomalies, aneuploidies arelikely to be detected in 2.1% cases [1] and are Trisomy 18in usually all cases [1]. An invasive testing is justified inthese cases before offering termination of pregnancy.Noninvasive prenatal test (NIPT) is not the best reliableoption for Trisomy 18 detection due to low fetal fractionand lower detection rate [5]. The presence of a choroidplexus cyst does not alter the risk of Trisomy 21, and thefinding should not be used to modify a patient’s risk ofTrisomy 21(2).
Flowchart of protocol for prenatally diagnosed CPC
Conflict of interest: None.
Ethical Statements: The study was approved by the Ethics Com-mittee, Paras Hospitals and written informed consents were takenfrom the patients included
