Adult leukodystrophies with neuroaxonal spheroids (LNS) constitute a heterogeneous group of genetic diseases. Herein, we report on two unrelated patients with LNS characterized by rapid onset, predominant involvement of the frontal white matter, and areas of decreased apparent diffusion coefficient on diffusion-weighted imaging. We found similar cases in the literature and propose that they represent a distinct entity within the group of LNS. Further studies will be required to identify its molecular basis.