Not all joint pain is arthritis

To the Editor: I was somewhat confused by the Clinical Picture case in the May 2013 issue.¹ The caption for Figure 1 stated that the MRI showed erosions and marrow edema, which were “asymmetrical compared with the other wrist, a finding highly suggestive of rheumatoid arthritis.” However, rheumatoid arthritis is generally considered to be symmetrical.² Was this a typographical error, or did I miss a crucial concept somewhere?