[The 457th case: polyarthralgia, back pain and subcutaneous masses]

A 54-year-old man was admitted to the Department of Rheumatology in Peking Union Medical College Hospital due to polyarthritis, back pain and multiple subcutaneous masses. He had symmetrical polyarthritis at onset, which was diagnosed as rheumatoid arthritis. His follow-up and treatment were irregular. Back pain and multiple subcutaneous masses developed 2 year ago. Erythrocyte sedimentation rate and C-reactive protein were elevated. Rheumatoid factor and Anti-cyclic citrullinated peptide antibody were positive. No evidence of infection or malignancy was detected. Chest CT suggested pulmonary fibrosis and osteolytic lesions of sternum. Spinal MRI showed paravertebral soft tissue. Biopsy of the soft tissue suggested the pathological finding of a rheumatoid nodule. The patient was diagnosed as rheumatoid arthritis complicated with multiple rheumatoid bursal cysts.Combination therapy of methylprednisolone(40mg/d) and cyclophosphamide(0.4 g/w) lead to a rapid improvement of clinical symptoms and laboratory parameters.The patient was still in remission at 6-month follow-up.