Evidence of central nervous system involvement in chronic demyelinating neuropathies associated with "benign" gammopathies.

Recent papers underline the possible involvement of the central nervous system when an acquired peripheral demyelinating disease occurs and vice-versa. We describe five patients with chronic polyneuropathy and "benign" gammopathy, monoclonal (IgM-K, IgA-k, IgG-k) in three cases and polyclonal (IgG, IgM) in two cases; the monoclonal gammopathies were detected in cases of peripheral nerve disease. Three patients showed tremor and signs of pyramidal system impairment when the peripheral damage had improved or was stable. All cases underwent a longitudinal assessment according to clinical, CSF, EMG-ENG, neuroradiological and pathological criteria. The MRI finding always showed multiple alterations of encephalic white matter. When related to neurophysiological and pathological data supporting a chronic demyelinating neuropathy, such results point to possible encephalic involvement in chronic polyneuropathies due to a pathogenetic mechanism common to both.