A patient with POEMS syndrome: the pathology of glomerular microangiopathy

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) is potentially fatal multisystem disorder but its renal complication has often been overlooked because renal involvement is not necessarily included in the diagnostic criteria of POEMS. This report documents the patient with POEMS syndrome with long-term renal histopathological changes evaluated by renal biopsy. A 32-year-old Japanese woman presented with symptoms consistent with POEMS syndrome associated with proteinuria and IgA-λ type monoclonal gammopathy. Initial renal biopsy for confirmation of diagnosis revealed the proliferation of glomerular capillary loops located in the expanded mesangial matrices associated with glomerular enlargement. Electron microscopy examination of the renal biopsy revealed the presence of double contoured glomerular basement membrane containing peculiar fibrillary structure. The patient was therefore initially diagnosed as membranoproliferative glomerulonephritis (MPGN)-like lesion without any significant immunoglobulins and complements deposition. The patient was subsequently admitted to hospital on five occasions due to renal dysfunction and anasarca for the next four years of her clinical course. The severity of anasarca was correlated mainly with serum titer of vascular endothelial growth factor (VEGF) during this period. Acute renal failure occurred at the last admission and the second biopsy was performed. An increased mesangial matrix and frequent global sclerosis of the glomeruli with arteriolosclerosis was noted in this second biopsy compared to the first one. These findings of renal biopsies suggest that the glomerular microangiopathy of POEMS syndrome may occur in the context of systemic capillary leak syndrome superimposed on chronic endothelial injury.