Megalencephalic leucoencephalopathy with subcortical cysts (Van Der Knaap syndrome)


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.