Aventriculy is rare brain malformation entity characterized by complete absence of the ventricular system and choroid plexus. Imaging features often overlap with holoprosencephaly. The key anatomic differentiating feature is the presence of a variable sized monoventricle in holoprosencephaly. In view of the common embryologic basis , aventriculy has been considered as the severe form of the holoprosencephaly – atelencephaly spectrum. Imaging literature is limited to isolated case reports describing multisystem anomalies with speculations about genetic association.