Alexander Disease (male, 4 yrs)

Extensive leukodystrophy changes with a predominance in the frontal regions but also extending towards the parietal lobes and external capsules in keeping with Alexander's disease. These areas demonstrate free diffusivity. There is evidence of an optic pathway glioma. . A second lesion is demonstrated in the dorsal medulla. This is slightly exophytic. This lesion is more pronounced on the sagittal T1 weighted imaging but is probably of very similar size on the axial T2 weighted imaging. There is no hydrocephalus.