Multifocal motor neuropathy presenting as chronic progressive proximal leg weakness.

We report on a 47-year-old man with a 12-year history of progressive and ultimately severe proximal weakness of his right lower limb. Motor conduction block at the unaffected tibial nerve and positive IgM antibodies against GM1 gangliosides lead us to suggest a diagnosis of oligosymptomatic multifocal motor neuropathy. He rapidly responded to intravenous immunoglobulins, with complete remission lasting 4 weeks, and had a repeated treatment response to intravenous immunoglobulins during subsequent exacerbations. The proximal involvement may represent another unusual clinical manifestation of multifocal motor neuropathy.