Extensive callosal infarction showing difficulty in knitting as an initial symptom.

A 66-year-old right-handed woman with type 2 diabetes mellitus was admitted to our hospital with progressive dysarthria and gait disturbance preceded by difficulty in knitting. Brain magnetic resonance imaging (MRI) showed a lesion involving the entire corpus callosum. Although tumor was considered in the differential diagnosis because of the atypical imaging findings, she was diagnosed with infarction based on clinical improvement after admission and sequential changes in MRI. We suggest that difficulty in knitting may be an important early manifestation of a callosal disconnection syndrome and that follow-up clinical and imaging examinations would contribute to confirmation of the diagnosis.