Multifocal motor neuropathy (MMN) is a recently recognised autoimmune neuropathy. The importance of this rare entity is the clinical similarity with disease of the motor neuron and the possibility of successful treatment. The authors present the case-histories of two patients: in one a typical clinical and electrophysiological picture of MMN with a mild peripheral paresis in the distribution of some peripheral nerves was involved, mainly on the upper extremities and asymmetrically, without impaired sensitivity and with the electrophysiological picture of multiple partial motor conduction block. The authors found a satisfactory response to repeated treatment with intravenous human immunoglobulin (IVIG). The complexity of the differential diagnosis from chronic inflammatory demyelinating polyne- uropathy (CIDP) is illustrated on the case-history of the second patient with a probable diagnosis of CIDP who met some clinical and in particular electrophysiological criteria of MMN and had a marked and very rapid response to IVIG administration.

        Key words: multifocal motor neuropathy, intravenous human immunoglobulin, chronic inflammatory demyelinating polyneuropathy, motor conduction block