Relapsing chronic low-dose corticosteroid-responsive multifocal motor neuropathy with conduction block.

Multifocal Motor Neuropathy (MMN) is a newly described disorder that might mimics the Motor Neuron Disease (MND). MMN is considered by some authors to be an entity distinct from Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP), nevertheless because a pure-motor variant of CIDP is well recognized and CIDP can present Partial Motor Conduction Block (PMCB), several authors believe that MMN can be a variant of CIDP. We describe a 27-year old male with a relapsing chronic low-dose corticosteroid-responsive MMN with conduction block. Our case stresses that MMN includes a wide range of motor neuropathies with different immunological profiles conditioning distinct treatment strategies.