Hereditary diffuse leukoencephalopathy with spheroids characterized by spastic hemiplegia preceding mental impairment

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a young-adult-onset autosomal dominant white matter disease characterized by progressive cognitive dysfunction. We herein report the case of a 20-year-old woman who developed spastic hemiplegia. Brain magnetic resonance imaging revealed increased bilateral T2 signal intensity and bright diffusion-weighted imaging signals with a low apparent diffusion coefficient within the frontoparietal white matter. The lesion gradually expanded for over one year. The patient was initially diagnosed with multiple sclerosis (MS); however, she did not respond to immunosuppressive therapy. DNA sequencing showed a heterozygous c.2381T>C mutation in colony-stimulating factor 1 receptor. HDLS with a pure motor phenotype is sometimes difficult to differentiate from MS.