The prenatal diagnosis of transient cysts of the fetal choroid plexus

Ultrasound scanning during the second trimester of pregnancy revealed cysts of the choroid plexus in the posterior horn of the lateral ventricle in five cases. All disappeared spontaneously between 20 and 23 weeks and normal infants were subsequently delivered.     

Some observations of the structure of the choroid plexus and its cysts

The structure of the choroid plexus was studied in five normal human embryos, three normal fetuses and three fetuses with choroid plexus cysts. These were detected by ultrasound and the fetuses were karyotypically normal. The choroid plexus appears in the lateral cerebral ventricles at the seventh developmental week. The early structure is lobulated with vessels running in the mesenchymal stroma and forming capillary nets under the single-layered ependymal epithelium. This embryonal structure is converted into the fetal type during the ninth developmental week as the embryonal capillary net is replaced by elongated loops of wavy capillaries that lie under regular longitudinal epithelial folds. The choroid plexus cysts exhibited accumulation of fluid within distended mesenchymal stroma and did not show the wavy folds on this surface, which was smooth. Within this connective tissue of the cyst wall were distended angiomatous interconnecting thin-walled capillaries. Therefore, filled cavities were not lined by any epithelium. We suggest that fetal choroid plexuses cysts (at least in many cases) are in fact pseudocysts exhibiting angiomatous patterns of capillaries in their walls. Copyright © 2002 John Wiley & Sons, Ltd.     

The significance of prenatal diagnosis of choroid plexus cysts

A case is described of the prenatal diagnosis of choroid plexus cysts at 17 weeks' gestation which persisted beyond 36 weeks but could not be detected after delivery. At birth the child was found to have trisomy 18.     

Fetal choroid plexus cysts and trisomy 18: Assessment of risk based on ultrasound findings and maternal age

This paper examines the association between fetal choroid plexus cysts (CPCs) and trisomy 18 and proposes a method by which risks can be derived taking into account both sonographic findings and maternal age. Data from our centre on the sonographic findings of 58 fetuses with trisomy 18 and 387 fetuses with CPCs as well as data from published series were used. It was calculated that the prevalence of CPCs in the general population is approximately 1 per cent and at mid-gestation the incidence of CPCs in fetuses with trisomy 18 is approximately 50 per cent. In the 387 fetuses with CPCs, the incidence of trisomy 18 increased with maternal age and the likelihood ratio for trisomy 18 increased with the number of additional abnormalities, from 0·03 for those with isolated CPCs to 0·4 if there was one additional abnormality and 20·5 if there were two or more additional abnormalities. It was concluded that if the cysts are apparently isolated, the risk for trisomy 18 is only marginally increased and maternal age should be the main factor in deciding whether or not to offer fetal karyotyping. If one additional abnormality is found, the maternal age-related risk is increased, so that even for a 20-year-old the risk for trisomy 18 is at least as high as the risk for trisomy 21 in a 35-year-old. In this respect, it may be considered desirable to offer such patients the option of karyotyping.     

Isolated choroid plexus cysts—the need for routine offer of karyotyping

The management of isolated fetal choroid plexus cysts remains controversial. We have prospectively studied 15 565 pregnancies at two large obstetric units for the presence of choroid plexus cysts. In all cases where cysts were present at 19 weeks' gestation or greater, and were multiple, bilateral or solitary and greater than 5 mm maximum diameter, women were offered amniocentesis or placental biopsy, irrespective of the presence or absence of other abnormalities. Choroid plexus cysts were present in 152 (0·98 per cent) of cases. Four cases (2·6 per cent) of autosomal trisomy (three of trisomy 18, one of trisomy 21) were detected on prenatal karyotyping. In all cases, choroid plexus cysts were the only detectable prenatal anomaly. This study and a review of other large studies do not support the view that isolated choroid plexus cysts are a benign variant, the risk of trisomy being 1 in 82. Until further evidence is available, we recommend that cases of isolated fetal choroid plexus cysts at 19 weeks' gestation or greater should be offered prenatal karyotyping.     

A prospective study of the incidence and significance of fetal choroid plexus cysts

Cysts of the choroid plexus of the lateral ventricle can be detected in the fetus during routine scanning at 16–18 weeks' gestation with an approximate incident of one in every 120 pregnancies. It is likely that in a high percentage of cases cysts are bilateral and that their recent discovery is mainly due to improvements in imaging technology. Although the great majority of cases resolve and do not result in any morbidity, five cases of trisomy 18 and one case of trisomy 21 associated with fetal choroid plexus cysts have been reported. In this prospective study, choroid plexus cysts were detected in 42 fetuses, resulting in 40 normal infants and 2 cases of trisomy 18. It is concluded that there may be a relationship between fetal choroid plexus cysts and trisomy 18. In order to obtain a more precise and accurate result, a multi-centre prospective study is being organized.     

Prenatal sonographic diagnosis of a third ventricle choroid plexus papilloma

We report a case of fetal hydrocephalus secondary to a third ventricle choroid plexus papilloma detected by ultrasound at 33 weeks' gestation. The prenatal sonographic and colour flow Doppler findings of this rare fetal intracranial tumour are discussed.     

The significance of choroid plexus cysts in fetuses at 18–20 weeks. An indication for amniocentesis?

Over a period of 25 months, all antenatal patients were offered a detailed ultrasound scan at 18–20 weeks' gestation. The lateral cerebral ventricles were scanned for the presence of choroid plexus cysts. Fifty-one patients found to have choroid plexus cysts were offered amniocentesis to exclude chromosomal abnormalities. One pregnancy, in which the only abnormality found was bilateral choroid plexus cysts, was terminated after trisomy 18 was detected on amniocentesis at 19 weeks. The other 50 pregnancies had normal fetal outcomes. The significance of the isolated finding of choroid plexus cysts is reviewed.     

Management of prenatally detected trisomy 8 mosaicism

We report on ten pregnancies with trisomy 8 mosaicism. Nine cases were prenatally detected in chorionic villi (n=6), amniotic fluid (AF) cells (n=2) or fetal blood (FB) lymphocytes (n=1). Follow-up laboratory investigations showed confined placental mosaicism (CPM) or pseudomosaicism in eight cases. In one case with ultrasound abnormalities, trisomy 8 mosaicism was detected in FB cells although cultured AF cells showed normal cells only. Another case of mosaic trisomy 8 was prenatally missed; cytogenetic analysis of short-term cultured villi revealed a normal male karyotype, while postnatally, trisomy 8 mosaicism was detected in peripheral blood lymphocytes and skin fibroblasts of the affected child. These findings indicate the difficulties in the prenatal diagnosis of trisomy 8 mosaicism. When found in chorionic villi, it mostly represented CPM, while in a case of true fetal trisomy 8 mosaicism, the cytotrophoblast cells showed a normal karyotype. So, the cytotrophoblast compartment of chorionic villi is a poor indicator of the presence or absence of fetal trisomy 8 mosaicism. Follow-up investigations including amniocentesis and especially fetal blood sampling are required to come to a definite prenatal diagnosis of trisomy 8 mosaicism. Copyright © 2001 John Wiley & Sons, Ltd.     

AZFc deletion detected in a newborn with prenatally diagnosed Yq deletion

A case of prenatally diagnosed Yq deletion is described. Fluorescence in situ hybridisation (FISH) was used to identify the abnormal chromosome and to exclude mosaicism. Based on the cytogenetic result and the ultrasound investigation the pregnancy was continued. A newborn with normal male genitalia was delivered. Microdeletion analysis of the Yq showed the absence of the AZFc region. This type of deletion has been described as being associated with azoospermia or oligozoospermia with a progressive decrease of sperm number over time. Long-term andrological follow-up of the newborn will be necessary with eventual cryoconservation of sperm at early adulthood. The present report proposes that AZF analysis combined with FISH has an important role in accurate genetic counselling in sex chromosome anomalies. Copyright © 2001 John Wiley & Sons, Ltd.     

Postnatal management and outcome of prenatally diagnosed lung lesions

Advancements in fetal diagnostic imaging have increased prenatal diagnosis of many fetal anomalies. The purpose of this chapter is to review the etiology and natural history of prenatally diagnosed cystic lung lesions, including congenital cystic adenomatoid malformations (CCAM), pulmonary sequestrations (PSs), hybrid lesions, and bronchogenic cysts, and then discuss current concepts in the management and outcome of these lesions. Copyright © 2008 John Wiley & Sons, Ltd.