POEMS Syndrome

Abstract

POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes) syndrome is a rare cause of demyelinating and axonal neuropathy and multi-organ involvement, associated with plasma cell dyscrasia and upregulation of serum levels of vascular endothelial growth factor (VEGF). The pathogenesis of the disorder is not well understood, but increased vascular permeability and neovascularization mediated by VEGF and other inflammatory cytokines are likely to play an important role in most of the characteristic symptoms. However, the pathogenesis of peripheral neuropathy is unclear; VEGF may affect the blood-nerve barrier and allow neurotoxic substances to access the nerve parenchyma, resulting in nerve structural damages. POEMS syndrome is a potentially fatal disease, and there is no established treatment regimen for this syndrome. In appropriate candidates, high-dose chemotherapies with autologous peripheral blood stem cell transplantation are recommended, because this treatment can lead to obvious and rapid clinical improvement in neuropathy as well as other symptoms, with a significant decrease in serum VEGF levels. The indication for this treatment has not yet been established, and the long-term prognosis is unclear. Potential future therapies include the administration of thalidomide, lenalidomide, bortezomib, and anti-VEGF monoclonal antibody (bevacizumab). Prognosis of POEMS syndrome has been substantially improved by these novel interventions, whereas randomized control trials are required to establish a proper therapeutic guideline. This review focuses on recent advances in diagnosis and treatment of POEMS syndrome and discusses future perspectives of therapeutic strategy.