Colpocephaly is a rare and potentially severe structural brain abnormality characterized by an unusual shape of the cerebral ventricles. Synonymous terms for this condition are limited, but they include macrocephaly, hydrocephalus ex vacuo, and ventriculomegaly. Macrocephaly or megalencephaly refer to an abnormally enlarged or large head, whereas hydrocephalus ex vacuo indicates an enlargement of the ventricles due to brain tissue loss. On the other hand, ventriculomegaly describes mild-to-moderate dilation of the brain's ventricles. While these terms share similarities with colpocephaly, they describe different aspects of brain anatomy or lead to different disease outcomes. Colpocephaly is often associated with other neurological impairments, including mental retardation and cerebral palsy.