Megalencephalic leukoencephalopathy with subcortical cysts in an adult: quantitative proton MR spectroscopy and diffusion tensor MRI.

A 37-year-old macrocephalic woman was investigated for increasing gait disturbance due to longstanding spasticity and ataxia. MRI showed widespread bilateral increase in signal from cerebral white matter on T2-weighted images. Numerous subcortical cysts were visible in anterior-temporal and parietal regions. These clinical and neuroradiological features are those of megalencephalic leukoencephalopathy with subcortical cysts (MLC), a recently delineated white-matter disease with onset in childhood. Quantitative localised proton MR spectroscopy of white matter revealed marked reduction of N-acetylaspartate, creatine, and choline with normal values for myo-inositol, consistent with axonal loss and astrocytic proliferation. Diffusion tensor imaging showed an increased apparent diffusion coefficient and reduced anisotropy in affected white matter pointing to reduced cell density with an increased extracellular space. These findings are in line with histological changes alterations known to occur in MLC.