[Effective treatment of POEMS syndrome accompanied by plasmacytoma with lenalidomide, dexamethasone, and local irradiation].

A 70-year-old woman experienced pain in both gastrocnemius muscles, numbness in the toes, and muscle weakness in both the legs that lasted for two months. After getting admitted to our hospital, the muscle weakness extended to both her arms, and nerve conduction studies revealed decreased nerve conduction velocity, which was more prominent in the elbow and the axilla than in the wrist. A magnetic resonance imaging revealed a tumor in the right femoral neck, which was histologically diagnosed as plasmacytoma. Laboratory findings revealed IgA lambda type M protein and an elevated VEGF level of 2,320 pg/ml; edema was present in both the legs. After a diagnosis of POEMS syndrome, lenalidomide and dexamethasone treatment were initiated simultaneously, along with irradiation. The treatment improved polyneuropathy, along with a decrease in the VEGF level. Increased vascular permeability due to elevated VEGF led to the development of neuropathy of POEMS syndrome, and treatment against proliferating monoclonal plasma cells is effective. In the present case, we believe that a prompt control of the plasmacytoma with novel therapeutic agents for myeloma with irradiation resulted in the improvement of the neurological symptoms.