A biopsy was performed on sclerotic bone, which finally showed monoclonal plasma cell proliferation, followed by disease progression, and serum M proteins soon turned positive.[13] From the aforementioned, it is inferred that the development of M protein-negative POEMS syndrome may be due to low or no secretion of M protein by extramedullary monoclonal plasma cells, and therefore, the pathogenesis is not different from the classical POEMS syndrome. Here, MYOM2 is linked to POEMS syndrome.