Chronic multifocal neuropathy with persistent conduction block (Lewis-Sumner syndrome). A clinico-morphologic study of two further cases with review of the literature.

We present data of 2 patients suffering from chronic motor-sensory multifocal neuropathy with persistent conduction block. The first case concerns a 9-year follow-up of a female, aged 24 years at onset with persistent multiple conduction blocks and a tendency towards generalization of clinical deficits. Eight years after onset sural nerve biopsy revealed extreme interfascicular variations of de/remyelination, onion bulb formation, fiber loss, edema, and proliferation of basal lamina of endoneurial capillaries. Serum antibodies against GM1 gangliosides were not detected. The second case, a 29-year-old Yemenitic male with a 5-year history, exhibited conduction blocks in motor and sensory fibers, and a normal sural nerve biopsy. Our results are discussed with respect to those of some 30 cases individually reported in the literature.