IMPORTANT: We currently have a number of bugs related to image cropping and are actively trying to resolve them. In the meantime, we have disabled cropping. Apologies for any inconvenience. Stay informed: radiopaedia.org/chat

Hemimegalencephaly

Case contributed by Mohammad A. ElBeialy
Diagnosis almost certain

Presentation

Early neonatal seizures.

Patient Data

Age: 5 days
Gender: Male
ultrasound

Transcranial ultrasound of the brain revealed enlargement of the left lateral ventricle. No evidence of germinal matrix hemorrhage, no intraventricular hemorrhage or hypoxic-ischemic insult.

CT Brain

ct

CT examination of the brain shows enlarged dysplastic left cerebral hemisphere with gross cortical dysplasia and enlargement of the left lateral ventricle. Cavum septum pellucidum and cavum verge are noted as normal variants. A right parietooccipital subgaleal cephalohematoma is seen mostly related to ventose application. 

MRI Brain

mri

Hamartomatous over-growth of the entire left cerebral hemisphere is noted associated with cortical dysplasia (agyria/pachygyria) with a broadening of the cortical sulci and shallow gyri & enlargement of the ipsilateral left lateral ventricle with left lateral ventricle small focal subependymal heterotopia. Contralateral displacement of the posterior falx with slight contralateral left-to-right midline shift is noted. Associated calcification of the left inferior frontal deep white matter is noted as well as a small left posterior frontal developmental venous anomaly (DVA).

A small right parieto-occipital subgaleal cephalohematoma is seen.    

Normal right cerebral hemisphere.    

Normal cerebellum, brain stem and cervico-medullary junction.

Case Discussion

A case of hemimegalencephaly of the left cerebral hemisphere with cortical dysplasia or malformation (agyria / pachygyria), deep white matter calcifications as well as subependymal grey matter heterotopia & small DVA.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.