An unusual presentation of multiple myeloma: a case report.

Multiple myeloma can occasionally manifest with joint disease. We report the case of an individual with a progressive bilateral carpal syndrome and a symmetrical severe seronegative polyarthritis and joint swelling. Investigations revealed an erosive seronegative inflammatory arthritis in association with bilateral carpal tunnel syndrome, anaemia, hepatic impairment and nephrotic-range proteinuria. Synovial fluid cytology demonstrated plasmablasts and multinucleated cells with products of chondrolysis. The diagnosis of multiple myeloma (with secondary amyloidosis) was made on serum protein electrophoresis and bone marrow biopsy.The relationship between myeloma and joint disease is discussed, highlighted by the presence in this case of all three pathogenic features associated with arthritis in myeloma patients- an erosive arthritis, carpal tunnel syndrome and an invasive tumoural arthritis.