[A case of relapsing demyelinating multiple mononeuropathy with multifocal nerve enlargement].

We report a 23-year-old woman, who had a relapsing-remitting multiple mononeuropathy with multifocal nerve enlargement. The patient was characterized by asymmetrical, marked enlargement of multiple nerves in the arms (median and ulnar nerves) and neck (accessory nerve) bilaterally. Sequential nerve conduction studies revealed persistent demyelinative abnormalities, especially across the segment of nerve thickening. The MRI of the proximal arm confirmed the markedly enlarged median and ulnar nerves which showed high signal intensity on T2-weighted images and partial enhancement after administration of gadolinium. We consider that the patient had the clinical features of "multifocal pseudohypertrophic neuropathy" described by Adams et al, and that chronic demyelination and inflammation associated with impairment of the blood-nerve barrier might be underlying mechanisms.