Multiple myeloma presented as polyart hritis: case reports and literature review / 中华风湿病学杂志

ABSTRACT

Objective We reported 5 unusual cases of multiple myeloma (MM) initially presented as polyarthritis.Special attention should be paid to this very unusual scenario.Methods Five cases who presented initially as polyarthritis and finally diagnosed as MM were administered to Peking University People's Hospital and 11 cases from literature were reported.The clinical symptoms and laboratory parameters were analyzed respectively.Results The primarily affected joints were small joints,such as metacarpophalangeal joints,proximal interphalangeal joint,metatarsophalangeal and temporomandibular joints,but large joints such as wrists,elbows,shoulders,knees,ankle joints could be involved,too.Fourteen of 16 patients were misdiagnosed as rheumatoid arthritis (RA).Renal dysfunction presenting as high level of serum creatinine or proteinuria was detected in 14 cases.Laboratory tests showed elevated erythrocyte sedimentation rate or C reactive protein level in 13 cases.Anemia was detected in 9 cases.Hypercalcemia was detected in half of the patients.Hyperglobu-linemia was detected in 6 cases.The serum level of free M-protein was markedly elevated in 14 cases.Auto-antibodies were negative,except that rheumatoid factor was positive in 1 case.Conclusion It is important to pay attention to the clinical pictures presented as polyarthritis with negative autoantibodies,and associated with renal dysfunction,anemia and hypergammaglobulinemia.MM is important in the differential diagnosis.