POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome is a rare cause of demyelinating and axonal mixed neuropathy with monoclonal plasma cell proliferative disorder and multiorgan involvement. The pathogenesis of POEMS syndrome is not well understood, but overproduction of vascular endothelial growth factor (VEGF), probably secreted by plasmacytomas, is likely to be responsible for most of the characteristic symptoms. POEMS syndrome is a potentially fatal disease, and patients' quality of life deteriorates because of progressive neuropathy, massive pleural effusion or ascites, or thromboembolic events. There is a need for efficacious therapy to improve prognosis. This is the first update of a review first published in 2008.