Megalencephalic leucoencephalopathy with subcortical cysts (Van Der Knaap syndrome)
Diagnosis certain
Presentation
Delayed developmental milestones.
Patient Data
Age: 3 years
Gender: Female
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- Bilateral extensive deep white matter T2 hyperinsity is seen involving the subcortical white matter as well as the subcortical U-fibers with relatively large subcortical cysts of CSF signal intensity are seen predominantly in the bilateral frontal as well as anterior temporal lobes. The lesions are seen sparing the basal ganglia as well as both thalami. No pathological enhancement.
- Mild to moderate dilatation of the ventricular system as well as prominent cortical sulci and basal cisterns.
- No significant infra-tentorial abnormality.
Case Discussion
The radiological findings are typical for Megalencephalic leukoencephalopathy with subcortical cyst (MLC) or Van der Knaap syndrome
MLC is a neurodegenerative leukoencephalopathy with genetic mutation affecting astrocyte dysfunction. It is a rare spongiform leukoencephalopathy with diffuse white matter swelling.
The hallmark of radiological diagnosis is:
- Subcortical white matter involved early in course of disease with involvement of the subcortical U-fibers.
- Subcortical cysts especially temporal poles and frontoparietal lobes.
- The main differential diagnosis is metachromatic leukodystrophy (MLD). However, not all symmetrical leukodystrophies are MLD. If U-fibers or cysts involved, MLC is considered.