Nine-year case history of monofocal motor neuropathy.

A 36-year-old man had a 6-year history of progressive left hand and finger extension weakness. Extensive electrophysiological studies showed only a partial motor conduction block along the left radial nerve at the mid-arm. Several intravenous immunoglobulin treatments were clinically successful. A 3-year follow-up did not show any clinical or electrophysiological involvement of other nerves. A monofocal motor neuropathy, as a variant of multifocal motor neuropathy, was diagnosed.