Subcortical lesions due to cobalamin deficiency: an unusual MRI lesion pattern

We present a 44-year-old male patient with new onset of right focal epilepsy and bilateral hand hypesthesia. Cerebral MRI showed bilateral T2w/DWI hyperintense subcortical lesions in the cingulate gyrus, insula, and amygdala, whereas spinal MRI revealed a cervical posterior column lesion, corresponding to subacute combined degeneration. Laboratory workup revealed a cobalamin deficiency due to type A gastritis, and no evidence of antibodies associated with limbic encephalitis. After sufficient cobalamin substitution, the cerebral and spinal lesions gradually regressed. Our case represents a unique cerebral subcortical MRI lesion pattern in a patient with epilepsy and cobalamin deficiency. Thus, the latter represents an important differential diagnosis for autoimmune encephalitis.