Objective: To assess the clinical significance of fetal isolated borderline cerebral lateral ventriculomegaly defined as a width of the atrium of the lateral cerebral ventricles of 10-15 mm in the absence of other sonographically demonstrable malformations.
Design: Retrospective study of the outcome of fetuses with a sonographic diagnosis of isolated borderline cerebral lateral ventriculomegaly and review of the English-language literature.
Results: Of 31 fetuses, two had chromosomal aberrations (trisomy 21 and trisomy 13) and three had neurological complications (one infant developed shunt-dependent hydrocephalus, one lissencephaly and one cerebral hemorrhage and periventricular leukomalacia). The literature search revealed eight independent studies. Including the present series, 234 cases were available for analysis. An abnormal outcome was documented in 22.8% of cases. Perinatal death occurred in 3.7%. Chromosomal aberrations, mostly trisomy 21, were present in 3.8%, malformations undetected at a second-trimester sonogram in 8.6% and neurological sequelae, mostly a mild to moderate delay in cognitive and/or motor development, were present in 11.5%. The risk of an abnormal neurological outcome was increased in females versus males (22.6% versus 4.6%, relative risk 4.892; 95% confidence interval 1.356-17.656), when the atrial width was 12 mm or more (13.9% versus 3.8%, relative risk 3.6, 95% confidence interval 1.035-12.846) and when the diagnosis was made in the second trimester versus later in gestation.
Conclusions: In most cases, isolated borderline cerebral lateral ventriculomegaly has no consequence. However, this finding carries an increased risk of cerebral maldevelopment, delayed neurological development and, possibly, chromosomal aberrations. The optimal management of these cases remains uncertain.