The corpus callosum was shorter than expected for the gestational age of 20 weeks, the cavum septum pellucidum was very small, and the lateral ventricles
and third ventricle were mildly enlarged.
The lateral ventricle
and extracerebral CSF spaces also get larger ex vacuo due to the brain volume loss.
Dandy, in 1918, demonstrated in an animal study that unilateral hydrocephalus was produced when the 4th ventricle was blocked together with the access through the foramen of Monro to the contralateral plexectomized lateral ventricle
Microscopic examination showed bilateral dilatation of the lateral ventricles
and mesencephalic aqueduct associated with marked periventricular white mater microspongiosis.
Females' brains showed evidence of inflammation, and males' lateral ventricles
were 2-3 times larger than normal.
In the first patient, the colloid cyst was growing slowly and finally caused a sudden and complete blockage of CSF outflow from the lateral ventricles
Holoprosencephaly, which presents with clear communication between the frontal horns or the entire lateral ventricles
, is without a doubt one of the earliest detectable brain pathologies (along with anencephaly).
That report stated, inter alias "The lateral ventricles
are enlarged, including the atria, occipital horns and body.
They may circulate freely throughout the cerebrospinal fluid (CSF) pathways or become attached to the ependyma anywhere in the ventricles, but their predilection is for the occipital horn of the lateral ventricles
and fourth ventricle.
Brain CT demonstrated expansion of lateral ventricles
of cerebrum (LV) and subarachnoid space as well as presence of the reduced density centers in white (substantia alba) and gray (substantia grisea) substances.
In the newborn, before closure of the anterior fontanelle occurs, screening ultrasonography may clearly show ACC; it may also show parallel lateral ventricles
, interhemispheric cysts, hydrocephalus, and other related anomalies.
Figure 1 is an axial computed tomogram image without contrast of the brain through the level of the lateral ventricles
obtained four months prior to presentation that demonstrates no acute intracranial process.