A case report of an M protein-negative patient with POEMS syndrome associated with renal involvement.

Background: POEMS syndrome with polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes is an uncommon plasma cell paraneoplastic syndrome involving multiple system. It is relatively rare in clinical practice, and renal involvement is a usual yet easily overlooked symptom.

Case presentation: We successfully treated a patient with M protein-negative POEMS syndrome with membranoproliferative glomerulonephritis (MPGN) findings and thrombotic microangiopathic changes by comparing the level of Vascular endothelial growth factor (VEGF) in the serum and the changes in polyserositis before and after the patient's treatment.

Conclusion: POEMS syndrome clinically involves multiple systems and has complex symptoms. Because of the diversity of the disease manifestations, identification of atypical POEMS syndrome and timely intervention are important for patient survival and prognosis.