Vitamin B12 deficiency mimicking neuroimaging features of motor neuron disease.

A 45-year-old man presented with 2-month-history of progressive gait disturbances and behavioral changes. Examination showed vibration sense compromise and pyramidal signs of release. Blood test revealed low serum vitamin B12 (120 pg/mL; normal range>200 pg/mL). Brain MRI disclosed hyperintense signal in corticospinal tracts, a similar pattern observed in motor neuron disease (MND) (Figure). Replacement therapy was started and there were motor and cognitive improvements. Vitamin B12 deficiency may present with different neurological syndromes1. Encephalopathy related to B12 deficiency presents with nonspecific white matter changes2. Although MTC brain MRI sequence was normal, our patient presented neuroimaging features observed in MND3.