Tumefactive Brain Demyelination Accompanying MADSAM Neuropathy

Multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy is characterized by asymmetric multifocal motor and sensory loss and conduction blocks in peripheral nerves. Peripheral demyelinating diseases may be accompanied by demyelination in central nervous system (CNS). In this report, a MADSAM patient with a solitary tumefactive demyelinating lesion in brain is presented. Neuroimaging due to a visual field defect revealed a right parietooccipital lesion, which was initially misdiagnosed as a tumor. Pathological examination showed that it was demyelinating in nature. Peripheral nervous symptoms of the patient developed two years later and she was then diagnosed with MADSAM. There was prominent clinical and electrophysiological response to steroid treatment. Tumefactive brain involvement was not previously reported for MADSAM neuropathy, although it was documented in a single case with typical chronic inflammatory demyelinating polyneuropathy (CIDP). CNS involvement should therefore be considered in MADSAM patients.