Transient lesion in the splenium of the corpus callosum in acute cerebellitis.

We report the reversible magnetic resonance imaging (MRI) findings in a 2-year-old girl with acute cerebellitis. The high signal intensity in the cerebellum was obvious on diffusion-weighted images, and the splenium of the corpus callosum also showed high signal intensity on T2-weighted images and on diffusion-weighted images. The lesion in the splenium quickly returned to normal 72 hours later, whereas the hyperintensity in the cerebellum persisted for 1 week until clinical improvement was achieved. The findings in our patient suggested the particular vulnerability of the splenium of the corpus callosum compared to other regions and the importance of the MRI examinations including diffusion-weighted images in the early stage of encephalitis.