Hemihydranencephaly; a Case Report.

Background: hemihydranencephaly is a rare disorder of the brain characterized by complete or almost complete unilateral absence of cerebral cortex with preservation of meninges, basal ganglia, pons, medulla, cerebellum, and falx.case presentation: thirteen year-old male child presented with left sided upper and lower limb weakness with facial asymmetry since the age of six months. his magnetic resonance imaging (mri) scans demonstrated a nearly complete absence of the right cerebral hemisphere including basal ganglion, which was replaced by cerebrospinal fluid with a small residual rim of the occipital cortex. the imaging features were suggestive of right-sided hemihydranencephaly. conclusion: patients with hemihydranencephaly provide an experiment of nature with potential implications for normal cognitive development and illustrate how much there is still to be learned about human development.