[Renal involvement in POEMS syndrome]

Area of Science:

• Nephrology
• Hematology
• Pathology

Background:

• POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal grammapathy, Skin changes) is a rare multisystem disorder.
• Renal involvement in POEMS syndrome is documented but often subtle, presenting as acute renal failure or chronic insufficiency with proteinuria.
• Distinctive glomerular pathology is a key feature of renal involvement in POEMS syndrome.

Observation:

• A case of POEMS syndrome with peculiar renal pathological findings is presented.
• Published literature includes 17 other cases of POEMS syndrome with renal involvement, predominantly from Japan.
• Clinical presentations vary, ranging from acute renal failure with edema to chronic renal insufficiency with mild proteinuria.

Findings:

• Renal biopsy reveals prominent glomerular changes, differing from membranoproliferative glomerulonephritis (MPGN) and thrombotic microangiopathy (TMA).
• Light microscopy shows mesangial proliferation and capillary wall thickening, resembling MPGN.
• Immunofluorescence is negative for immunoglobulin and complement deposits; electron microscopy shows lucent subendothelial spaces, suggesting endothelial injury rather than TMA.

Implications:

• The unique glomerular lesions are termed 'mesangiolytic glomerulonephritis'.
• Microangiopathic lesions are hypothesized to result from chronic glomerular endothelial cell injury.
• Increased IL-6 production may explain the efficacy of corticosteroid therapy in acute POEMS syndrome-related kidney disease.