Teaching NeuroImages: Transient mutism associated with splenium lesion in capecitabine-induced leukoencephalopathy

A 50-year-old woman presented with recurrent episodes of mutism on the 7th day of capecitabine therapy (1,250 mg/m(2) twice a day) for advanced gastric cancer. Interictal neurologic examination documented mild left hemiparesis and right Babinski sign. Brain CT, ictal EEG, electrolytes, ammoniemia, and vitamins B-1 and B-12 were all unremarkable. Brain MRI revealed symmetric bilateral hyperintensities of the splenium of the corpus callosum and of the corticospinal tracts on diffusion-weighted imaging and T2-fluid-attenuated inversion recovery sequences (figure). Symptoms subsided 2 days after chemotherapy withdrawal. Transient mutism has been reported following callosotomy for drug-resistant epilepsy(1) or in toxic leukoencephalopathies typically involving the callosal fibers.(2)