Renal involvement in POEMS syndrome.

We describe a patient with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) who was found to have renal involvement with particular renal pathological findings. So far, 17 other cases, most of them from Japan, of POEMS syndrome with renal involvement, have been published. Clinical features are variable: acute renal failure with anasarca or moderate chronic renal insufficiency with mild proteinuria. This latter presentation often passes unnoticed. There is no severe hypertension, no microangiopathic hemolytic anemia. Renal biopsy shows prominent glomerular changes which are unusual and distinct from membranoproliferative glomerulonephritis (MPGN) and from glomerular thrombotic microangiopathy (TMA). Mesangial proliferation and thickening of the capillary wall with double contour on light microscopy suggest an MPGN. By immunofluorescent microscopy, no immunoglobulins or complement deposits were found. The occurrence of mesangiolytic lesions has led to the term of "mesangiolytic glomerulonephritis". The presence, on electron microscopy, of lucent subendothelial spaces could indicate TMA. But there are neither thrombi nor arteriolar changes. We are inclined to consider that the microangiopathic lesions are due to chronic injury of glomerular endothelial cells, exacerbated at outbreaks of the disease. Increased production of IL 6 could support the efficacy of corticosteroid therapy, particularly in acute clinical situations.