A 2-day-old, full-term, otherwise asymptomatic female was followed up for “ventricular asymmetry” detected on prenatal ultrasound.
There are oblong cysts parallel to superolateral margins of lateral ventricles. No associated haemorrhage, gliosis or hydrocephalus.
Connatal cysts are benign, isolated findings which likely represent a normal variant, also referred to as "coarctation of the lateral ventricles". No associated intracranial hemorrhage or gliosis is seen. These typically resolve by 1-2 months corrected gestational age/ post-term. No adverse neurological outcome is associated .
The major differential considerations include subependymal cysts and periventricular leukomalacia, both of which are clinically more significant than connatal cysts. The location of the abnormality is the key distinguishing feature (see illustration); with connatal cysts noted at the superolateral margins of the frontal horns of lateral ventricles, subependymal cysts noted at the level of/extending posterior to the foramen of Monro and periventricular leukomalacia involving white matter above the ventricles, the centrum semiovale and in a posterior/occipital distribution .
There are two types of subependymal cysts: posthemorrhagic or congenital, related to germinolysis. These can be an isolated finding in otherwise healthy newborns. In other instances, these can be related to haemorrhage, infection, hypoxia, chromosomal or metabolic abnormalities .
Periventricular leukomalacia is the most ominous of these cystic lesions and represents an ischemic injury involving the watershed area of the preterm brain-the periventricular white matter. This may be challenging to diagnose by ultrasound in the acute/early phase . In chronic cases, cyst formation may be noted within the affected white matter, brain ventricles may be enlarged and there may be a loss of deep white matter . There is a history of marked prematurity and difficult labour.
Differential Diagnosis List