Jaccoud's Arthropathy in a Case of Mixed Connective Tissue Disorder: An Interesting Tale.

In Jaccoud's arthropathy (JA), classical deformities that resemble rheumatoid arthritis (RA), such as swan neck deformity and ulnar deviation, are present, but in contrast to RA, these are  to passive movement and nonerosive arthritis. Similar deformities are also described in various connective tissue disorders. Mixed connective tissue disease (MCTD) characteristically has overlapping features of various connective tissue diseases (CTDs) such as systemic lupus erythematosus, systemic sclerosis, and myosotis with an association of U1RNP antibody. Approximately 60% of patients with MCTD may have deforming arthritis. We present a case of a 23-year-old male, with multiple overlapping clinical features and deforming arthritis. This case begs the question to identify various possible differentials of deforming arthritis.