Subacute combined degeneration of the spinal cord: MRI detection of preferential involvement of the posterior columns in a child.

Subacute combined degeneration of the spinal cord (vitamin B12-deficient myelopathy) is a neurologic disorder manifesting progressive symptoms of paresthesia and spastic paralysis. As shown by pathology, it initially involves the posterior columns of the thoracic cord. We present a case of vitamin B12 deficiency with preferential posterior column involvement of the thoracic cord in a child. Theoretically, this should be the earliest, most reversible stage of the disease, making recognition of this MRI pattern of critical importance.