POEMS syndrome: origination from clonal plasma cells or B cells?

POEMS syndrome is a rare disorder which has been increasingly recognized. The clonal origin is controversial. Some people argue that POEMS syndrome originates from abnormal plasma cell clones. So, treatment frequently targets the plasma cell clone. Nevertheless, others believe that both plasma cells and B cells can be the potential culprit in POEMS syndrome.A 65-year-old male came to the emergency department of our hospital with the complaints of bilateral soles numbness and weight loss for half a year, abdominal distension for half a month, and chest tightness and shortness of breath for one day. He was then diagnosed as POEMS syndrome complicated with monoclonal B-cell lymphocytosis (non-CLL type). A standard bendamustine plus rituximab (BR) regimen combined with low dose of lenalidomide was administered.After four cycles of treatment, the ascites of the patient was absent and the neurological symptom disappeared. The renal function, the IgA level, and the VEGF level all returned to normal.POEMS syndrome, a multi-system disorder, is easily misdiagnosed. The clonal origin of POEMS syndrome is controversial and needs further study. For now, there are no approved treatment regimens. Treatments mainly target the plasma cell clone. This case suggested that other therapy besides anti-plasma cell treatment may also be effective in POEMS syndrome.We report a patient with POEMS syndrome who achieved complete response after treatment with the combination of a standard BR regimen and low dose of lenalidomide. POEMS syndrome's pathological mechanisms and therapies warrant further studies.